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Malic Acid

100 Scientific Studies About Malic Acid

Malic Acid

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Results for your query on May 24, 1999
Search all fields for: malic acid
Published in 1980 through 1999
Only select references with abstracts available
Show references published in English only
Documents: 1 to 100 of 656
1 Bagchi S, et al; Structure and expression of murine malic enzyme mRNA. Differentiation-dependent accumulation of two forms of malic enzyme mRNA in 3T3-L1 cells. (J Biol Chem, 1987 Feb, Abstract available) [MEDLINE]
2 Pines O, et al; The cytosolic pathway of L-malic acid synthesis in Saccharomyces cerevisiae: the role of fumarase. (Appl Microbiol Biotechnol, 1996 Nov, Abstract available) [MEDLINE]
3 Eisele TA; Determination of D-malic acid in apple juice by liquid chromatography: collaborative study. (J AOAC Int, 1996 Jan, Abstract available) [MEDLINE]
4 Côrte Real M, et al; Transport of malic acid and other dicarboxylic acids in the yeast Hansenula anomala. (Appl Environ Microbiol, 1990 Apr, Abstract available) [MEDLINE]
5 Sousa MJ, et al; Transport of malic acid in the yeast Schizosaccharomyces pombe: evidence for a proton-dicarboxylate symport. (Yeast, 1992 Dec, Abstract available) [MEDLINE]
6 McKenna MC, et al; Regulation of mitochondrial and cytosolic malic enzymes from cultured rat brain astrocytes. (Neurochem Res, 1995 Dec, Abstract available) [MEDLINE]
7 Meurman JH, et al; Experimental sports drinks with minimal dental erosion effect. (Scand J Dent Res, 1990 Apr, Abstract available) [MEDLINE]
8 Chou WY, et al; Selective oxidative modification and affinity cleavage of pigeon liver malic enzyme by the Cu(2+)-ascorbate system. (J Biol Chem, 1995 Oct, Abstract available) [MEDLINE]
9 Delcourt F, et al; Influence of pH, malic acid and glucose concentrations on malic acid consumption by Saccharomyces cerevisiae. (Appl Microbiol Biotechnol, 1995 May, Abstract available) [MEDLINE]
10 Goodridge AG, et al; Malic enzyme and fatty acid synthase in the uropygial gland and liver of embryonic and neonatal ducklings. Tissue-specific regulation of gene expression. (Arch Biochem Biophys, 1984 Apr, Abstract available) [MEDLINE]

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11 Goodridge AG, et al; Regulation of genes for enzymes involved in fatty acid synthesis. (Ann N Y Acad Sci, 1986, Abstract available) [MEDLINE]
12 Elkins ER, et al; Detection of adulteration in apple juice by L-malic/total malic acid ratio: collaborative study. (J AOAC Int, 1994 Mar, Abstract available) [MEDLINE]
13 Pines O, et al; Overexpression of cytosolic malate dehydrogenase (MDH2) causes overproduction of specific organic acids in Saccharomyces cerevisiae. (Appl Microbiol Biotechnol, 1997 Aug, Abstract available) [MEDLINE]
14 Drmota T, et al; Iron-ascorbate cleavable malic enzyme from hydrogenosomes of Trichomonas vaginalis: purification and characterization. (Mol Biochem Parasitol, 1996 Dec, Abstract available) [MEDLINE]
15 Kawai S, et al; Purification and characterization of a malic enzyme from the ruminal bacterium Streptococcus bovis ATCC 15352 and cloning and sequencing of its gene. (Appl Environ Microbiol, 1996 Aug, Abstract available) [MEDLINE]
16 Morris SM Jr, et al; Developmental and nutritional regulation of the messenger RNAs for fatty acid synthase, malic enzyme and albumin in the livers of embryonic and newly-hatched chicks. (Mol Cell Biochem, 1984 Sep, Abstract available) [MEDLINE]
17 Roncero C, et al; Regulation of the malic enzyme and fatty acid synthase genes in chick embryo hepatocytes in culture: corticosterone and carnitine regulate responsiveness to triiodothyronine. (Arch Biochem Biophys, 1992 Jun, Abstract available) [MEDLINE]
18 Kendrick A, et al; Desaturation of polyunsaturated fatty acids in Mucor circinelloides and the involvement of a novel membrane-bound malic enzyme. (Eur J Biochem, 1992 Oct, Abstract available) [MEDLINE]
19 Vazquez Oderiz ML, et al; Simultaneous determination of organic acids and vitamin C in green beans by liquid chromatography. (J AOAC Int, 1994 Jul, Abstract available) [MEDLINE]
20 Lee HS, et al; Apple juice composition: sugar, nonvolatile acid, and phenolic profiles. (J Assoc Off Anal Chem, 1988 Jul, Abstract available) [MEDLINE]

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21 Harrod CJ, et al; Derepressed utilization of L-malic acid and succinic acid by mutants of Pachysolen tannophilus. (J Ind Microbiol Biotechnol, 1997 Jun, Abstract available) [MEDLINE]
22 Wang X, et al; Production of L-malic acid via biocatalysis employing wild-type and respiratory-deficient yeasts. (Appl Biochem Biotechnol, 1998 Spr, Abstract available) [MEDLINE]
23 Viljoen M, et al; Molecular analysis of the malic enzyme gene (mae2) of Schizosaccharomyces pombe. (Yeast, 1994 May, Abstract available) [MEDLINE]
24 Wei CH, et al; Affinity cleavage at the putative metal-binding site of pigeon liver malic enzyme by the Fe(2+)-ascorbate system. (Biochemistry, 1994 Jun, Abstract available) [MEDLINE]
25 Chou WY, et al; Cloning and expression of pigeon liver cytosolic NADP(+)-dependent malic enzyme cDNA and some of its abortive mutants. (Arch Biochem Biophys, 1994 Apr, Abstract available) [MEDLINE]
26 Winning BM, et al; Plant mitochondrial NAD+-dependent malic enzyme. cDNA cloning, deduced primary structure of the 59- and 62-kDa subunits, import, gene complexity and expression analysis. (J Biol Chem, 1994 Feb, Abstract available) [MEDLINE]
27 Loeber G, et al; Human NAD(+)-dependent mitochondrial malic enzyme. cDNA cloning, primary structure, and expression in Escherichia coli. (J Biol Chem, 1991 Feb, Abstract available) [MEDLINE]
28 Ma XJ, et al; Nutritional regulation and tissue-specific expression of the malic enzyme gene in the chicken. Transcriptional control and chromatin structure. (J Biol Chem, 1990 Oct, Abstract available) [MEDLINE]
29 Peleg Y, et al; A simple plate-assay for the screening of L-malic acid producing microorganisms. (FEMS Microbiol Lett, 1990 Feb, Abstract available) [MEDLINE]
30 Salmon JM; L-malic-acid permeation in resting cells of anaerobically grown Saccharomyces cerevisiae. (Biochim Biophys Acta, 1987 Jul, Abstract available) [MEDLINE]

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31 Hodnett DW, et al; The chicken malic enzyme gene: structural organization and identification of triiodothyronine response elements in the 5'-flanking DNA. (Arch Biochem Biophys, 1996 Oct, Abstract available) [MEDLINE]
32 Sánchez LB, et al; Sequence of a malic enzyme gene of Giardia lamblia. (Mol Biochem Parasitol, 1996 Nov, Abstract available) [MEDLINE]
33 Nunes M, et al; Swine cytosolic malic enzyme: cDNA cloning, sequencing, and localization. (Mamm Genome, 1996 Nov, Abstract available) [MEDLINE]
34 Chou WY, et al; Nonidentity of the cDNA sequence of human breast cancer cell malic enzyme to that from the normal human cell. (J Protein Chem, 1996 Apr, Abstract available) [MEDLINE]
35 Hillgartner FB, et al; Overexpression of the alpha-thyroid hormone receptor in avian cell lines. Effects on expression of the malic enzyme gene are selective and cell-specific. (J Biol Chem, 1992 Jun, Abstract available) [MEDLINE]
36 Swierczynski J, et al; Triiodothyronine-induced accumulations of malic enzyme, fatty acid synthase, acetyl-coenzyme A carboxylase, and their mRNAs are blocked by protein kinase inhibitors. Transcription is the affected step. (J Biol Chem, 1991 Sep, Abstract available) [MEDLINE]
37 Rothermel BA, et al; Primary structure of the maize NADP-dependent malic enzyme. (J Biol Chem, 1989 Nov, Abstract available) [MEDLINE]
38 Deng Y, et al; Tolerance of acid-adapted and non-adapted Escherichia coli O157:H7 cells to reduced pH as affected by type of acidulant. (J Appl Microbiol, 1999 Feb, Abstract available) [MEDLINE]
39 Prati C, et al; Effects of dentin surface treatments on the shear bond strength of Vitrabond. (Dent Mater, 1992 Jan, Abstract available) [MEDLINE]
40 Jenik RA, et al; Terminal differentiation in the avian uropygial gland. Accumulation of fatty acid synthase and malic enzyme in non-dividing cells. (Cell Tissue Res, 1987 Nov, Abstract available) [MEDLINE]

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41 Knichel W, et al; D-Malic enzyme of Pseudomonas fluorescens. (Eur J Biochem, 1982 Apr, Abstract available) [MEDLINE]
42 Sundqvist KE, et al; Role of NADP+ (corrected)-linked malic enzymes as regulators of the pool size of tricarboxylic acid-cycle intermediates in the perfused rat heart [published erratum appears in Biochem J 1987 Aug 1:245(3):following 934] (Biochem J, 1987 May, Abstract available) [MEDLINE]
43 Mitsch MJ, et al; Chimeric structure of the NAD(P)+- and NADP+-dependent malic enzymes of Rhizobium (Sinorhizobium) meliloti. (J Biol Chem, 1998 Apr, Abstract available) [MEDLINE]
44 Magnuson MA, et al; Coding nucleotide sequence of rat liver malic enzyme mRNA. (J Biol Chem, 1986 Jan, Abstract available) [MEDLINE]
45 Piyarom S, et al; Effects of grinding and humidification on the transformation of conglomerate to racemic compound in optically active drugs. (J Pharm Pharmacol, 1997 Apr, Abstract available) [MEDLINE]
46 Burch HB, et al; The distribution of six enzymes of oxidative metabolism along the rat nephron. (J Histochem Cytochem, 1984 Jul, Abstract available) [MEDLINE]
47 Newbold CJ, et al; Mode of action of the yeast Saccharomyces cerevisiae as a feed additive for ruminants. (Br J Nutr, 1996 Aug, Abstract available) [MEDLINE]
48 Long JJ, et al; Cloning and analysis of the C4 photosynthetic NAD-dependent malic enzyme of amaranth mitochondria. (J Biol Chem, 1994 Jan, Abstract available) [MEDLINE]
49 Bakken IJ, et al; [U-13C]glutamate metabolism in rat brain mitochondria reveals malic enzyme activity. (Neuroreport, 1997 May, Abstract available) [MEDLINE]
50 Fabregat I, et al; The NADPH consumption regulates the NADPH-producing pathways (pentose phosphate cycle and malic enzyme) in rat adipocytes. (Mol Cell Biochem, 1987 Mar, Abstract available) [MEDLINE]

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51 Schaffer WT; Effects of growth hormone on lipogenic enzyme activities in cultured rat hepatocytes. (Am J Physiol, 1985 Jun, Abstract available) [MEDLINE]
52 Iritani N, et al; Nutritional regulation of lipogenic enzyme gene expression in rat epididymal adipose tissue. (J Biochem (Tokyo), 1996 Aug, Abstract available) [MEDLINE]
53 Lee WS, et al; Membrane enzymes associated with the dissimilation of some citric acid cycle substrates and production of extracellular oxidation products in chemostat cultures of Pseudomonas fluorescens. (Can J Microbiol, 1984 Mar, Abstract available) [MEDLINE]
54 Iritani N, et al; Comparative study of lipogenic enzymes in several vertebrates. (Lipids, 1984 Nov, Abstract available) [MEDLINE]
55 Roncero C, et al; Hexanoate and octanoate inhibit transcription of the malic enzyme and fatty acid synthase genes in chick embryo hepatocytes in culture. (J Biol Chem, 1992 Jul, Abstract available) [MEDLINE]
56 Alderete JF, et al; Cloning and molecular characterization of two genes encoding adhesion proteins involved in Trichomonas vaginalis cytoadherence. (Mol Microbiol, 1995 Jul, Abstract available) [MEDLINE]
57 Smith JA, et al; Characterization of the vacuolar ATPase activity of the crassulacean-acid-metabolism plant Kalanchoë daigremontiana. Receptor modulating. (Eur J Biochem, 1984 Jun, Abstract available) [MEDLINE]
58 Strait KA, et al; Kinetics of induction by thyroid hormone of the two hepatic mRNAs coding for cytosolic malic enzyme in the hypothyroid and euthyroid states. Evidence against an obligatory role of S14 protein in malic enzyme gene expression. (J Biol Chem, 1989 Nov, Abstract available) [MEDLINE]
59 Morioka H, et al; Structural characterization of the rat malic enzyme gene. (Proc Natl Acad Sci U S A, 1989 Jul, Abstract available) [MEDLINE]
60 Hrdý I, et al; Primary structure of the hydrogenosomal malic enzyme of Trichomonas vaginalis and its relationship to homologous enzymes. (J Eukaryot Microbiol, 1995 Sep, Abstract available) [MEDLINE]

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61 Uljas HE, et al; Survival of Escherichia coli O157:H7 in synthetic gastric fluid after cold and acid habituation in apple juice or trypticase soy broth acidified with hydrochloric acid or organic acids. (J Food Prot, 1998 Aug, Abstract available) [MEDLINE]
62 Castelein H, et al; The peroxisome proliferator activated receptor regulates malic enzyme gene expression. (J Biol Chem, 1994 Oct, Abstract available) [MEDLINE]
63 Walter MH, et al; Characterization of a bean (Phaseolus vulgaris L.) malic-enzyme gene. (Eur J Biochem, 1994 Sep, Abstract available) [MEDLINE]
64 Queiros O, et al; Isolation and characterization of Kluyveromyces marxianus mutants deficient in malate transport. (Yeast, 1998 Mar, Abstract available) [MEDLINE]
65 Kim SJ, et al; The effect of glycolic acid on cultured human skin fibroblasts: cell proliferative effect and increased collagen synthesis. (J Dermatol, 1998 Feb, Abstract available) [MEDLINE]
66 Denayrolles M, et al; Cloning and sequence analysis of the gene encoding Lactococcus lactis malolactic enzyme: relationships with malic enzymes. (FEMS Microbiol Lett, 1994 Feb, Abstract available) [MEDLINE]
67 Cássio F, et al; A comparative study on the transport of L(-)malic acid and other short-chain carboxylic acids in the yeast Candida utilis: evidence for a general organic acid permease. (Yeast, 1993 Jul, Abstract available) [MEDLINE]
68 Nakamura K, et al; Taste responses of neurons in the nucleus of the solitary tract of awake rats: an extended stimulus array. (J Neurophysiol, 1993 Sep, Abstract available) [MEDLINE]
69 Caetano NN, et al; Effect of methotrexate (MTX) on NAD(P)+ dehydrogenases of HeLa cells: malic enzyme, 2-oxoglutarate and isocitrate dehydrogenases. (Cell Biochem Funct, 1997 Dec, Abstract available) [MEDLINE]
70 Stols L, et al; Production of succinic acid through overexpression of NAD(+)-dependent malic enzyme in an Escherichia coli mutant. (Appl Environ Microbiol, 1997 Jul, Abstract available) [MEDLINE]

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71 Peleg Y, et al; Inducible overexpression of the FUM1 gene in Saccharomyces cerevisiae: localization of fumarase and efficient fumaric acid bioconversion to L-malic acid. (Appl Environ Microbiol, 1990 Sep, Abstract available) [MEDLINE]
72 Hernandez A, et al; Regulation of malic-enzyme-gene expression by cAMP and retinoic acid in differentiating brown adipocytes. (Eur J Biochem, 1993 Jul, Abstract available) [MEDLINE]
73 Chen L, et al; Low-dose almitrine bismesylate enhances hypoxic pulmonary vasoconstriction in closed-chest dogs. (Anesth Analg, 1990 Nov, Abstract available) [MEDLINE]
74 Furbank RT, et al; C4 acid decarboxylation and photosynthesis in bundle sheath cells of NAD-malic enzyme-type C4 plants: mechanism and the role of malate and orthophosphate. (Arch Biochem Biophys, 1990 Feb, Abstract available) [MEDLINE]
75 Kulkarni G, et al; Cloning and nucleotide sequence of a full-length cDNA encoding Ascaris suum malic enzyme. (Arch Biochem Biophys, 1993 Jan, Abstract available) [MEDLINE]
76 Towle HC, et al; Changes in the hepatic levels of messenger ribonucleic acid for malic enzyme during induction by thyroid hormone or diet. (Biochemistry, 1980 Feb, Abstract available) [MEDLINE]
77 Madvig P, et al; Relationship of malic enzyme activity to fatty acid synthesis and the pathways of glucose catabolism in developing rat liver. (J Nutr, 1980 Jan, Abstract available) [MEDLINE]
78 Iritani N, et al; Effects of dietary proteins on lipogenic enzymes in rat liver. (J Nutr, 1986 Feb, Abstract available) [MEDLINE]
79 Seböková E, et al; Regulation of gene expression for lipogenic enzymes in the liver and adipose tissue of hereditary hypertriglyceridemic, insulin-resistant rats: effect of dietary sucrose and marine fish oil. (Biochim Biophys Acta, 1996 Sep, Abstract available) [MEDLINE]
80 Satterlee J, et al; Duck liver malic enzyme: sequence of a tryptic peptide containing the cysteine residue labeled by the substrate analog bromopyruvate. (Biochim Biophys Acta, 1991 Sep, Abstract available) [MEDLINE]

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81 Revilla E, et al; The NADPH-producing pathways (pentose phosphate and malic enzyme) are regulated by the NADPH consumption in rat mammary gland. (Biochem Int, 1987 May, Abstract available) [MEDLINE]
82 Batenburg JJ, et al; Levels of mRNAs coding for lipogenic enzymes in rat lung upon fasting and refeeding and during perinatal development [published erratum appears in Biochim Biophys Acta 1990 Feb 6;1042(2):269] (Biochim Biophys Acta, 1989 Dec, Abstract available) [MEDLINE]
83 Arunakaran J, et al; Effects of androgens, prolactin and bromocriptine on seminal vesicular enzymes of the pyruvate malate cycle involved in lipogenesis in castrated mature monkeys, Macaca radiata. (Int J Androl, 1988 Apr, Abstract available) [MEDLINE]
84 Katsurada A, et al; Effects of dietary nutrients on lipogenic enzyme and mRNA activities in rat liver during induction. (Biochim Biophys Acta, 1986 Jul, Abstract available) [MEDLINE]
85 Häusler RE, et al; CO2 is the inorganic carbon substrate of NADP malic enzymes from Zea mays and from wheat germ. (Eur J Biochem, 1987 Mar, Abstract available) [MEDLINE]
86 Greengard O, et al; Hormonal and dietary regulation of hepatic enzymes in tumor-bearing rats. (Cancer Res, 1983 Apr, Abstract available) [MEDLINE]
87 Watford M, et al; The regulation of glucose and pyruvate formation from glutamine and citric-acid-cycle intermediates in the kidney cortex of rats, dogs, rabbits and guinea pigs. (Biochem J, 1980 Jun, Abstract available) [MEDLINE]
88 Davis BB, et al; Insulin-mediated post-transcriptional regulation of hepatic malic enzyme and albumin mRNAs. (Biochem Biophys Res Commun, 1988 Aug, Abstract available) [MEDLINE]
89 Bratcher SC, et al; The pyruvate-proton exchange reaction of malic enzyme from pigeon liver. (Biochim Biophys Acta, 1982 Mar, Abstract available) [MEDLINE]
90 Muramatsu M, et al; Hepatic lipogenesis and mobilization of peripheral fats in the formation of alcoholic fatty liver. (Jpn J Pharmacol, 1981 Dec, Abstract available) [MEDLINE]

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91 Sousa MJ, et al; Effects of ethanol and acetic acid on the transport of malic acid and glucose in the yeast Schizosaccharomyces pombe: implications in wine deacidification. (FEMS Microbiol Lett, 1995 Feb, Abstract available) [MEDLINE]
92 Katsurada A, et al; Effects of insulin and fructose on transcriptional and post-transcriptional regulation of malic enzyme synthesis in diabetic rat liver. (Biochim Biophys Acta, 1989 Jul, Abstract available) [MEDLINE]
93 Cássio F, et al; Low- and high-affinity transport systems for citric acid in the yeast Candida utilis. (Appl Environ Microbiol, 1991 Dec, Abstract available) [MEDLINE]
94 Fukuda H, et al; Nutritional and hormonal regulation of mRNA levels of lipogenic enzymes in primary cultures of rat hepatocytes. (J Biochem (Tokyo), 1992 Jan, Abstract available) [MEDLINE]
95 Wei CH, et al; Identification of Asp258 as the metal coordinate of pigeon liver malic enzyme by site-specific mutagenesis. (Biochemistry, 1995 Jun, Abstract available) [MEDLINE]
96 Fukuda H, et al; Effects of aging on contributions of dietary fat and triiodothyronine treatment to lipogenic enzyme induction. (Biochim Biophys Acta, 1987 Sep, Abstract available) [MEDLINE]
97 Sul HS, et al; Cloning of cDNA sequences for murine malic enzyme and the identification of aberrantly large malic enzyme mRNA in MOD-1 null mice. (J Biol Chem, 1984 Jan, Abstract available) [MEDLINE]
98 Kelling CK, et al; Regulation of hepatic malic enzyme by perfluorodecanoic acid. (J Biochem Toxicol, 1986 Sep, Abstract available) [MEDLINE]
99 González-Manchón C, et al; AP-1 and T3RE cis elements operate as a functional unit in the transcriptional control of the human malic enzyme gene. (Gene, 1999 Jan 8, Abstract available) [MEDLINE]
100 Kiick DM, et al; Determination of dissociation constants for enzyme-reactant complexes for NAD-malic enzyme by modulation of the thiol inactivation rate. (Biochemistry, 1984 Nov, Abstract available) [MEDLINE]

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NLM database Documents


Record 1 from database: MEDLINE
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Title
Structure and expression of murine malic enzyme mRNA. Differentiation-dependent accumulation of two forms of malic enzyme mRNA in 3T3-L1 cells.
Author
Bagchi S; Wise LS; Brown ML; Bregman D; Sul HS; Rubin CS
Address
Source
J Biol Chem, 1987 Feb, 262:4, 1558-65
Abstract
Many murine cells express two mRNAs with markedly different sizes (2.0 and 3.1 kilobases (kb)) that hybridize with cDNA probes for cytosolic malic enzyme ((S)-malate NADP+ oxidoreductase (oxaloacetate-decarboxylating, EC 1.1.1.40). A series of overlapping cDNA clones corresponding to 3129 nucleotides of malic enzyme mRNA was isolated and sequenced to determine the relationship between the two mRNAs and establish the primary structure of mouse malic enzyme. The larger mRNA has an open reading frame of 1716 nucleotides followed by a 3' untranslated region of 1348 nucleotides. The sequence of an exceptionally G/C-rich (88%) portion (65 nucleotides) of the 5' noncoding region was also established. An uncommon poly A addition signal (AUUAAA) is used during the processing of the 3.1-kb mRNA. The 2.0-kb mRNA results from the utilization of another poly A addition signal that truncates the 3' noncoding sequence by approximately 1 kb. The mRNA coding sequence indicates that the malic enzyme subunit contains 572 amino acid residues and has a Mr of 64,000. Two putative components of an NADP-binding domain are located between residues 100 and 165. During the differentiation of 3T3-L1 preadipocytes into adipocytes both the rate of synthesis and relative mRNA concentration for malic enzyme and another lipogenic enzyme, ATP-citrate lyase, are coordinately increased 5-7-fold. However, as preadipocytes approach confluence, the mRNA levels for both lipogenic enzymes transiently increase 3-4-fold, whereas the rates of synthesis of the two proteins are only slightly elevated. Thus, lipogenic enzyme expression is controlled at a pretranslational level during adipogenesis, but the accumulation of the same enzymes may also be subject to translational control in the fibroblast-like preadipocytes. In contrast, mRNA coding for a third enzyme required for lipogenesis, glycerol-3-phosphate dehydrogenase, is not detected in 3T3-L1 preadipocytes, but rapidly accumulates during adipocyte development.
Language of Publication
English
Unique Identifier
87109297

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MeSH Heading (Major)
Malate Dehydrogenase|BI/*GE; Nucleic Acid Conformation|*
MeSH Heading
Adipose Tissue|CY/EN; Amino Acid Sequence; Animal; Base Sequence; Cell Differentiation; Cell Line; Gene Expression Regulation; Glycerolphosphate Dehydrogenase|BI/GE; Mice; Multienzyme Complexes|BI/GE; Oxo-Acid-Lyases|BI/GE; Support, U.S. Gov't, P.H.S.

Publication Type
JOURNAL ARTICLE
ISSN
0021-9258
Country of Publication
UNITED STATES


Record 2 from database: MEDLINE
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Title
The cytosolic pathway of L-malic acid synthesis in Saccharomyces cerevisiae: the role of fumarase.
Author
Pines O; Even Ram S; Elnathan N; Battat E; Aharonov O; Gibson D; Goldberg I
Address
Department of Molecular Biology, Hebrew University-Hadassah Medical School, Jerusalem, Israel. ophry@md2.huji.ac.il
Source
Appl Microbiol Biotechnol, 1996 Nov, 46:4, 393-9
Abstract
Saccharomyces cerevisiae accumulates L-malic acid but not only minute amounts of fumaric acid. A 13C-nuclear magnetic resonance study following the label from glucose to L-malic acid indicates that the L-malic acid is synthesized from pyruvic acid via oxaloacetic acid. From this, and from previously published studies, we conclude that a cytosolic reductive pathway leading from pyruvic acid via oxaloacetic acid to L-malic acid is responsible for the L-malic acid production in yeast. The non-production of fumaric acid can be explained by the conclusion that, in the cell, cytosolic fumarase catalyzes the conversion of fumaric acid to L-malic but not the reverse. This conclusion is based on the following findings. (a) The cytosolic enzyme exhibits a 17-fold higher affinity towards fumaric acid than towards L-malic acid; the Km for L-malic acid is very high indicating that L-malic acid is not an in vivo substrate of the enzyme. (b) Overexpression of cytosolic fumarase does not cause accumulation of fumaric acid (but rather more L-malic acid). (c) According to 13C NMR studies there is no interconversion of cytosolic L-malic and fumaric acids.
Language of Publication
English
Unique Identifier
97141384

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MeSH Heading (Major)
Cytosol|EN/*ME; Fumarate Hydratase|GE/*ME; Malates|*ME; Saccharomyces cerevisiae|EN/*ME
MeSH Heading
Carbonyl Cyanide m-Chlorophenyl Hydrazone|PD; Citric Acid Cycle|PH; Ionophores|PD; Kinetics; Mitochondria|EN; Oxaloacetates|ME; Pyruvic Acid|ME; Substrate Specificity; Support, Non-U.S. Gov't; Support, U.S. Gov't, Non-P.H.S.

Publication Type
JOURNAL ARTICLE
ISSN
0175-7598
Country of Publication
GERMANY


Record 3 from database: MEDLINE
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Title
Determination of D-malic acid in apple juice by liquid chromatography: collaborative study.
Author
Eisele TA
Address
Tree Top, Inc., Technical Center, Selah, WA 98942, USA.
Source
J AOAC Int, 1996 Jan, 79:1, 50-4
Abstract
Eleven laboratories collaboratively studied a liquid chromatographic (LC) method for determination of D-malic acid in apple juice. The mobile phase consisted of mM L-valine and 8 mM copper acetate adjusted to pH 5.5 with NaOH. The UV detector was set at 330 nm, and a single reversed-phase LC column was used. Seven paired samples containing various amounts of D-malic acid ranging from 0 to 188 mg/100 mL of 12 Brix pasteurized apple juice were tested by each collaborator. Repeatability and reproducibility coefficients of variation ranged from 1.0 to 3.5% and 7.7 to 11.7%, respectively, within the range of 26 to 188 mg D-malic acid/100 mL of 12 Brix apple juice. The collaborative study results demonstrated that the method could quantitate the economic adulteration of apple juice with DL-malic acid at lower levels than those reported with previous methods. The LC method for determination of D-malic acid in apple juice has been adopted first action by AOAC INTERNATIONAL.
Language of Publication
English
Unique Identifier
96230021

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MeSH Heading (Major)
Beverages|*AN; Chromatography, High Pressure Liquid|*MT; Food Additives|*AN; Fruit|*; Malates|*AN
MeSH Heading
Sensitivity and Specificity; Stereoisomerism

Publication Type
JOURNAL ARTICLE
ISSN
1060-3271
Country of Publication
UNITED STATES


Record 4 from database: MEDLINE
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Title
Transport of malic acid and other dicarboxylic acids in the yeast Hansenula anomala.
Author
Côrte Real M; Leão C
Address
Laboratory of Biology, University of Minho, Braga Codex, Portugal.
Source
Appl Environ Microbiol, 1990 Apr, 56:4, 1109-13
Abstract
DL-Malic acid-grown cells of the yeast Hansenula anomala formed a saturable transport system that mediated accumulative transport of L-malic acid with the following kinetic parameters at pH 5.0: Vmax, 0.20 nmol.s-1.mg (dry weight)-1; Km, 0.076 mM L-malate. Uptake of malic acid was accompanied by proton disappearance from the external medium with rates that followed Michaelis-Menten kinetics as a function of malic acid concentration. Fumaric acid, alpha-ketoglutaric acid, oxaloacetic acid, D-malic acid, and L-malic acid were competitive inhibitors of succinic acid transport, and all induced proton movements that followed Michaelis-Menten kinetics, suggesting that all of these dicarboxylates used the same transport system. Maleic acid, malonic acid, oxalic acid, and L-(+)-tartaric acid, as well as other Krebs cycle acids such as citric and isocitric acids, were not accepted by the malate transport system. Km measurements as a function of pH suggested that the anionic forms of the acids were transported by an accumulative dicarboxylate proton symporter. The accumulation ratio at pH 5.0 was about 40. The malate system was inducible and was subject to glucose repression. Undissociated succinic acid entered the cells slowly by simple diffusion. The permeability of the cells by undissociated acid increased with pH, with the diffusion constant increasing 100-fold between pH 3.0 and 6.0.
Language of Publication
English
Unique Identifier
90253148

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MeSH Heading (Major)
Dicarboxylic Acids|*ME; Malates|*ME; Pichia|*ME; Saccharomycetales|*ME
MeSH Heading
Biological Transport, Active; Diffusion; Hydrogen-Ion Concentration; Kinetics; Succinates|ME; Support, Non-U.S. Gov't; Support, U.S. Gov't, Non-P.H.S.

Publication Type
JOURNAL ARTICLE
ISSN
0099-2240
Country of Publication
UNITED STATES


Record 5 from database: MEDLINE
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Title
Transport of malic acid in the yeast Schizosaccharomyces pombe: evidence for a proton-dicarboxylate symport.
Author
Sousa MJ; Mota M; Leão C
Address
Center of Chemical Engineering, University of Porto, Portugal.
Source
Yeast, 1992 Dec, 8:12, 1025-31
Abstract
The transport system for malic acid present in Schizosaccharomyces pombe cells, growing in batch culture on several carbon sources, has been studied. It was found that the dicarboxylic acid carrier of S. pombe is a proton-dicarboxylate symporter that allows uphill transport and accumulation as a function of delta pH with the following kinetic parameters at pH 5.0: Vmax = 0.1 nmol of total malic acid s-1 mg (dry weight) of cells-1 and Km = 1.0 mM total malic acid. Malic acid uptake (pH 5.0) was accompanied by disappearance of extracellular protons, the uptake rates of which followed Michaelis-Menten kinetics as a function of the acid concentration. The Km values calculated as the concentrations either of anions or of undissociated acid, at various extracellular pH values, pointed to the monoanionic form as the transported species. Furthermore, accumulated free acid suffered rapid efflux after the addition of the protonophore carbonyl cyanid m-chlorophenyl hydrazone. These results suggested that the transport system was a dicarboxylate-proton symporter. Growth of cells in a medium with glucose (up to 14%, w/v) and malic acid (1.5%, w/v) also resulted in proton-dicarboxylate activity, suggesting that the system, besides being constitutive, was still active at high glucose concentrations. The following dicarboxylic acids acted as competitive inhibitors of malic acid transport at pH 5.0: D-malic acid, succinic acid, fumaric acid, oxaloacetic acid, alpha-ketoglutaric acid, maleic acid and malonic acid. In addition, all of these dicarboxylic acids induced proton movements that followed Michaelis-Menten kinetics.(ABSTRACT TRUNCATED AT 250 WORDS)
Language of Publication
English
Unique Identifier
93190631

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MeSH Heading (Major)
Carrier Proteins|*ME; Malates|*ME; Schizosaccharomyces|*ME
MeSH Heading
Glucose|ME; Ion Transport; Kinetics; Proton Pump; Succinates|ME; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0749-503X
Country of Publication
ENGLAND


Record 6 from database: MEDLINE
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Title
Regulation of mitochondrial and cytosolic malic enzymes from cultured rat brain astrocytes.
Author
McKenna MC; Tildon JT; Stevenson JH; Huang X; Kingwell KG
Address
Department of Pediatrics, University of Maryland School of Medicine, Baltimor USA.
Source
Neurochem Res, 1995 Dec, 20:12, 1491-501
Abstract
Malate has a number of key roles in the brain, including its function as a tricarboxylic acid (TCA) cycle intermediate, and as a participant in the malate-aspartate shuttle. In addition, malate is converted to pyruvate and CO2 via malic enzyme and may participate in metabolic trafficking between astrocytes and neurons. We have previously demonstrated that malate is metabolized in at least two compartments of TCA cycle activity in astrocytes. Since malic enzyme contributes to the overall regulation of malate metabolism, we determined the activity and kinetics of the mitochondrial and cytosolic forms of this enzyme from cultured astrocytes. Malic enzyme activity measured at 37 degrees C in the presence of 0.5 mM malate was 4.15 +/- 0.47 and 11.61 +/- 0.98 nmol/min/mg protein, in mitochondria and cytosol, respectively (mean +/- SEM, n = 18-19). Malic enzyme activity was also measured in the presence of several endogenous compounds, which have been shown to alter intracellular malate metabolism in astrocytes, to determine if these compounds affected malic enzyme activity. Lactate inhibited cytosolic malic enzyme by a noncompetitive mechanism, but had no effect on the mitochondrial enzyme. alpha-Ketoglutarate inhibited both cytosolic and mitochondrial malic enzymes by a partial noncompetitive mechanism. Citrate inhibited cytosolic malic enzyme competitively and inhibited mitochondrial malic enzyme noncompetitively at low concentrations of malate, but competitively at high concentrations of malate. Both glutamate and aspartate decreased the activity of mitochondrial malic enzyme, but also increased the affinity of the enzyme for malate. The results demonstrate that mitochondrial and cytosolic malic enzymes have different kinetic parameters and are regulated differently by endogenous compounds previously shown to alter malate metabolism in astrocytes. We propose that malic enzyme in brain has an important role in the complete oxidation of anaplerotic compounds for energy.
Language of Publication
English
Unique Identifier
96381600

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MeSH Heading (Major)
Astrocytes|DE/*EN/UL; Cytosol|*EN; Homeostasis|*; Malate Dehydrogenase|*ME; Mitochondria|*EN
MeSH Heading
Animal; Aspartic Acid|PD; Cells, Cultured; Citrates|PD; Glutamic Acid|PD; Ketoglutaric Acids|PD; Lactates|PD; Malates|ME; Rats; Support, U.S. Gov't, P.H.S.

Publication Type
JOURNAL ARTICLE
ISSN
0364-3190
Country of Publication
UNITED STATES


Record 7 from database: MEDLINE
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Title
Experimental sports drinks with minimal dental erosion effect.
Author
Meurman JH; Härkönen M; Näveri H; Koskinen J; Torkko H; Rytömaa I; Järvinen V; Turunen R
Address
Department of Cariology, University of Helsinki, Finland.
Source
Scand J Dent Res, 1990 Apr, 98:2, 120-8
Abstract
The effects of new experimental sports drinks on dental enamel were studied in vitro using bovine tooth specimens. Profilometric analysis was used to measure the loss of tooth material after immersion of the specimens in the drinks. Thereafter the specimens' surface hardness was measured and scanning electron microphotographs were taken. In addition, 13 commercial sports drinks and experimental drinks containing either citric acid or malic acid were tested for their capacity to dissolve hydroxyapatite in vitro. The erosive effect increased markedly with decreasing pH. The citric acid containing drinks were more erosive than malic acid containing drinks. No erosion was observed with the malic acid containing drink (pH 5.90) but the drink of similar composition containing citric acid caused an erosion 1.3 +/- 1.1 microns deep and a commercial citric acid containing drink caused a lesion 12.3 +/- 4.5 microns deep after 120 min immersion. Softening of enamel was greater in specimens immersed in citric acid than in those immersed in malic acid containing drink. The in vitro hydroxyapatite dissolving effect of the commercial sports drink samples studied (all having a pH under 4.22) was markedly greater (0.48-4.38 mmol/l) than that of the malic acid containing experimental drink (pH 5.50, Ca++ concentration in the supernatant 0.19 mmol/l) and of the similar citric acid containing drink (0.35 mmol/l). The hydroxyapatite dissolving effect of both drinks started to be marked at a pH level of about 5.0 but increased thereafter exponentially with decreasing pH. At pH levels above 4.0 the hydroxyapatite dissolving effect of citric acid containing drinks was greater than that of malic acid containing drinks.
Language of Publication
English
Unique Identifier
90260579

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MeSH Heading (Major)
Beverages|*/AE/AN; Tooth Erosion|*ET/PA
MeSH Heading
Animal; Calcium|AN; Cattle; Chemistry, Physical; Citrates|AN; Hardness; Hydrogen-Ion Concentration; Hydroxyapatites|AN; Malates|AN; Microscopy, Electron, Scanning; Spectrophotometry, Atomic Absorption; Sports; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0029-845X
Country of Publication
DENMARK


Record 8 from database: MEDLINE
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Title
Selective oxidative modification and affinity cleavage of pigeon liver malic enzyme by the Cu(2+)-ascorbate system.
Author
Chou WY; Tsai WP; Lin CC; Chang GG
Address
Department of Biochemistry, National Defense Medical Center, Taipei, Taiwan, Republic of China.
Source
J Biol Chem, 1995 Oct, 270:43, 25935-41
Abstract
Pigeon liver malic enzyme was rapidly inactivated by micromolar concentration of Fe2+ in the presence of ascorbate at neutral pH. The inactivated enzyme was subsequently cleaved by the Fe(2+)-ascorbate system at the chemical bond between Asp258 and Ile259 (Wei, C.H., Chou, W.Y., Huang, S.M., Lin, C.C., and Chang, G.G. (1994) Biochemistry, 33, 7931-7936), which was confirmed by site-specific mutagenesis (Wei, C.H., Chou, W.Y., and Chang, G.G. (1995) Biochemistry 34, 7949-7954). In the present study, at neutral pH, Cu2+ was found to be more reactive in the oxidative modification of malic enzyme and the enzyme was cleaved in a similar manner as Fe2+ did. At acidic pH, however, Fe2+ was found to be ineffective in oxidative modification of the enzyme. Nevertheless, Cu2+ still caused enzyme inactivation and cleaved the enzyme at Asp141-Gly142, Asp194-Pro195, or Asp464-Asp465. Mn2+ and L-malate synergistically protect the enzyme from Cu2+ inactivation at acidic pH. Cu2+ is also a competitive inhibitor versus Mn2+ in the malic enzyme-catalyzed reaction with Ki value 70.3 +/- 5.8 microM. The above results indicated that, in addition to the previously determined Asp258 at neutral pH, Asp141, Asp194, and Asp464 are also the coordination sites for the metal binding of malic enzyme. We suggest that the mechanism of affinity modification and cleavage of malic enzyme by the Cu(2+)-ascorbate system proceed in the following sequence. First, Cu2+ binds with the enzyme at the Mn2+ binding site and reduces to Cu+ by ascorbate. Next, the local oxygen molecules are reduced by Cu+, thereby generating superoxide or other reactive free radicals. These radicals interact with the susceptible essential amino acid residues at the metal-binding site, ultimately causing enzyme inactivation. Finally, the modified enzyme is cleaved into several peptide fragments, allowing the identification of metal site of the enzyme. The pH-dependent different specificities of metal-catalyzed oxidation system may be generally applicable for other enzymes or proteins.
Language of Publication
English
Unique Identifier
96029696

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MeSH Heading (Major)
Ascorbic Acid|CH/*ME; Copper|CH/*ME; Enzyme Inhibitors|CH/*ME; Liver|*EN; Malate Dehydrogenase|AI/CH/DE/*ME
MeSH Heading
Amino Acid Sequence; Animal; Binding Sites; Cations, Divalent|ME; Malates|ME; Manganese|ME; Models, Chemical; Molecular Sequence Data; NADP|ME; Oxidation-Reduction; Pigeons; Sequence Homology, Amino Acid; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0021-9258
Country of Publication
UNITED STATES


Record 9 from database: MEDLINE
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Title
Influence of pH, malic acid and glucose concentrations on malic acid consumption by Saccharomyces cerevisiae.
Author
Delcourt F; Taillandier P; Vidal F; Strehaiano P
Address
ENSIGC, Laboratoire GÆenie Chimique, URA CNRS 192, Toulouse, France.
Source
Appl Microbiol Biotechnol, 1995 May, 43:2, 321-4
Abstract
Malic acid consumption by Saccharomyces cerevisiae was studied in a synthetic medium. The extent of malic acid degradation is affected by its initial concentration, the extent and the rate of deacidification increased with initial malate concentration up to 10 milligrams. For malic acid consumption, an optimal pH range of 3-3.5 was found, confirming that non-dissociated organic acids enter S. cerevisiae cells by simple diffusion. A full factorial design has been employed to describe a statistical model of the effect of sugar and malic acid on the quantity of malate degraded (milligrams) by a given amount of biomass (milligrams). The results indicated that the initial malic acid concentration is very important for the ratio of malate consumption to quantity of biomass. The yeast was found to be most efficient at higher levels of malate.
Language of Publication
English
Unique Identifier
95336707

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MeSH Heading (Major)
Glucose|*ME; Malates|*ME; Saccharomyces cerevisiae|*ME
MeSH Heading
Biomass; Fermentation; Hydrogen-Ion Concentration; Research Design; Support, Non-U.S. Gov't; Wine|MI

Publication Type
JOURNAL ARTICLE
ISSN
0175-7598
Country of Publication
GERMANY


Record 10 from database: MEDLINE
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Title
Malic enzyme and fatty acid synthase in the uropygial gland and liver of embryonic and neonatal ducklings. Tissue-specific regulation of gene expression.
Author
Goodridge AG; Jenik RA; McDevitt MA; Morris SM Jr; Winberry LK
Address
Source
Arch Biochem Biophys, 1984 Apr, 230:1, 82-92
Abstract
Malic enzyme [L-malate-NADP oxidoreductase (decarboxylating), EC 1.1.1.40] and fatty acid synthase activities were barely detectable in the uropygial gland of duck embryos until 4 or 5 days before hatching, when they began to increase. These activities increased about 30- and 140-fold, respectively, by the day of hatching. Malic enzyme and fatty acid synthase activities were also very low in embryonic liver. However, hepatic malic enzyme activity did not increase until the newly hatched ducklings were fed. Hepatic fatty acid synthase began to increase the day before hatching and the rate of increase in enzyme activity accelerated markedly when the newly hatched ducklings were fed. Starvation of newly hatched or 12-day-old ducklings had no effect on the activities of malic enzyme and fatty acid synthase in the uropygial gland but markedly inhibited these activities in liver. Changes in the concentrations of both enzymes and in the relative synthesis rates of fatty acid synthase correlated with enzyme activities in both uropygial gland and liver. Developmental patterns for sequence abundance of malic enzyme and fatty acid synthase mRNAs in uropygial gland and liver were similar to those for their respective enzyme activities. Starvation of 4-day-old ducklings had no significant effect on the abundance of these mRNAs in uropygial gland but caused a pronounced decrease in their abundance in liver. It is concluded that developmental and nutritional regulation of these enzymes is tissue specific and occurs primarily at a pretranslational level in both uropygial gland and liver.
Language of Publication
English
Unique Identifier
84177455

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MeSH Heading (Major)
Ducks|EM/*ME; Fatty Acid Synthetase Complex|*GE; Gene Expression Regulation|*; Liver|EM/*EN; Malate Dehydrogenase|*GE; Sebaceous Glands|EM/*EN
MeSH Heading
Animal; Animals, Newborn; Chemistry; Electrophoresis, Polyacrylamide Gel; Food Deprivation|PH; Organ Specificity; RNA, Messenger|ME; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.

Publication Type
JOURNAL ARTICLE
ISSN
0003-9861
Country of Publication
UNITED STATES


Record 11 from database: MEDLINE
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Title
Regulation of genes for enzymes involved in fatty acid synthesis.
Author
Goodridge AG; Back DW; Wilson SB; Goldman MJ
Address
Source
Ann N Y Acad Sci, 1986, 478:, 46-62
Abstract
The levels of malic enzyme and fatty acid synthase are increased by feeding and decreased by starvation in liver in vivo and are increased by triiodothyronine and decreased by glucagon in hepatocytes in culture. Cloned malic enzyme and fatty acid synthase cDNAs are being used to analyze regulation of these unique genes. Dietary regulation of both enzymes occurs at pretranslational steps. Increased transcription and increased mRNA stability contribute about equally to a 20-fold increase in malic enzyme mRNA level when starved ducklings are refed. In contrast, a 10-fold increase in the level of fatty acid synthase mRNA is largely accounted for by increased transcription of this gene. In chick-embryo hepatocytes incubated in serum-free medium containing insulin, triiodothyronine causes a greater than 10-fold increase in levels of both malic enzyme and fatty acid synthase mRNAs. Kinetic and inhibitor experiments suggest a protein intermediate in the increases of malic enzyme and fatty acid synthase mRNAs caused by triiodothyronine. For malic enzyme, the stimulation by triiodothyronine is predominantly posttranscriptional. Glucagon decreases the level of malic enzyme mRNA by 90 to 95%, with regulation occurring at a posttranscriptional step. Inhibitor experiments suggest that stimulation of the degradation of malic enzyme mRNA is partially responsible. Glucagon inhibited fatty acid synthase mRNA level by less than 50%; the inhibited step has not been identified. Thus, the coordinated regulation of malic enzyme and fatty acid synthase proteins by nutritional state may involve different hormones regulating at different points. A surprisingly large component of the regulation is posttranscriptional.
Language of Publication
English
Unique Identifier
87098420

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MeSH Heading (Major)
Fatty Acid Synthetase Complex|*GE; Gene Expression Regulation|*; Malate Dehydrogenase|*GE
MeSH Heading
Animal; Cells, Cultured; DNA|IP; DNA, Recombinant; Food; Glucagon|PH; Liver|EN; RNA, Messenger|ME; Starvation|EN; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.; Triiodothyronine|PH

Publication Type
JOURNAL ARTICLE; REVIEW
ISSN
0077-8923
Country of Publication
UNITED STATES


Record 12 from database: MEDLINE
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Title
Detection of adulteration in apple juice by L-malic/total malic acid ratio: collaborative study.
Author
Elkins ER; Heuser JR
Address
National Food Processors Association, Washington, DC 20005.
Source
J AOAC Int, 1994 Mar, 77:2, 411-5
Abstract
L-Malic acid is the predominate acid in pure apple juice and no D-malic acid should be present. Synthetic malic acid contains 50% D-malic acid, is inexpensive, and can be used to create nonauthentic apple juice. L-Malic/total malic ratios of 0.9 or less are indicative of a nonauthentic sample. Fourteen laboratories participated in a collaborative study to determine the L-malic/total malic acid ratio in apple juice. Ten samples of apple juice were sent to each laboratory. Authenticity of the samples varied from 0 to 100%. The coefficients of variation in all cases were acceptable, i.e., ca 5%. The method was adopted first action by AOAC INTERNATIONAL.
Language of Publication
English
Unique Identifier
94257987

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MeSH Heading (Major)
Beverages|*AN; Food Contamination|*; Fruit|*CH; Malates|*AN/CH

Publication Type
JOURNAL ARTICLE
ISSN
1060-3271
Country of Publication
UNITED STATES


Record 13 from database: MEDLINE
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Title
Overexpression of cytosolic malate dehydrogenase (MDH2) causes overproduction of specific organic acids in Saccharomyces cerevisiae.
Author
Pines O; Shemesh S; Battat E; Goldberg I
Address
Department of Molecular Biology, Hebrew University-Hadassah Medical School, Jerusalem, Israel. ophry@md2.huji.ac.il
Source
Appl Microbiol Biotechnol, 1997 Aug, 48:2, 248-55
Abstract
Saccharomyces cerevisiae accumulates L-malic acid through a cytosolic pathway starting from pyruvic acid and involving the enzymes pyruvate carboxylase and malate dehydrogenase. In the present study, the role of malate dehydrogenase in the cytosolic pathway was studied. Overexpression of cytosolic malate dehydrogenase (MDH2) under either the strong inducible GAL10 or the constitutive PGK promoter causes a 6- to 16-fold increase in cytosolic MDH activity in growth and production media and up to 3.7-fold increase in L-malic acid accumulation in the production medium. The high apparent Km of MDH2 for L-malic acid (11.8 mM) indicates a low affinity of the enzyme for this acid, which is consistent with the cytosolic function in the enzyme and differs from the previously published Km of the mitochondrial enzyme (MDH1, 0.28 mM). Under conditions of MDH2 overexpression, pyruvate carboxylase appears to be a limiting factor, thus providing a system for further metabolic engineering of L-malic acid production. The overexpression of MDH2 activity also causes an evaluation in the accumulation of fumaric acid and citric acid. Accumulation of fumaric acid is presumably caused by high intracellular L-malic acid concentrations and the activity of the cytosolic fumarase. The accumulation of citric acid may suggest the intriguing possibility that cytosolic L-malic acid is a direct precursor of citric acid in yeast.
Language of Publication
English
Unique Identifier
97444594

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MeSH Heading (Major)
Malate Dehydrogenase|GE/*PH; Malates|*ME; Saccharomyces cerevisiae|*ME
MeSH Heading
Citric Acid|ME; Cytosol|EN; Fumarates|ME; Kinetics; Support, Non-U.S. Gov't; Support, U.S. Gov't, Non-P.H.S.

Publication Type
JOURNAL ARTICLE
ISSN
0175-7598
Country of Publication
GERMANY


Record 14 from database: MEDLINE
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Title
Iron-ascorbate cleavable malic enzyme from hydrogenosomes of Trichomonas vaginalis: purification and characterization.
Author
Drmota T; Proost P; Van Ranst M; Weyda F; Kulda J; Tachezy J
Address
Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic.
Source
Mol Biochem Parasitol, 1996 Dec, 83:2, 221-34
Abstract
Two isoforms of NAD(P)(+)-dependent malic enzyme (EC 1.1.1.39) were isolated from hydrogenosomes of Trichomonas vaginalis. A positively charged isoform at pH 7 was obtained in a single purification step using cation-exchange chromatography. The second isoform, negatively charged at pH 7.5, was partially purified using a combination of anion-exchange and affinity chromatography. Both isoforms displayed similar physical and kinetic properties. Molecular weight determination of the native enzyme suggested a homotetrameric arrangement of the 60 kDa subunits. The enzyme utilized NAD+ (Km, 6-6.3 microM) preferentially to NADP+ (Km, 125-145 microM). The NAD(+)-dependent activity showed a broad pH optimum with maximum under alkaline conditions (pH 9) likely to be present inside hydrogenosomes. Immunocytochemical studies using a polyclonal rabbit antibody raised against purified T. vaginalis malic enzyme proved hydrogenosomal localization of the enzyme. Subfractionation of hydrogenosomes suggested an association of the malic enzyme with the hydrogenosomal membranes. The 60 kDa malic enzyme subunit was highly sensitive to non-enzymatic cleavage by an iron-ascorbate system resulting in two enzymatically inactive fragments of about 31 kDa. Microsequencing of the fragments revealed that the 60 kDa subunit was cleaved at the metal-binding site between Asp279-Ile280. The enzyme inactivation was inhibited by an excess of manganese. Iron-dependent posttranslational modification might contribute to the regulation of malic enzyme activity in vivo.
Language of Publication
English
Unique Identifier
97179499

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MeSH Heading (Major)
Malate Dehydrogenase|AN/CH/*IP/*ME; Trichomonas vaginalis|*EN
MeSH Heading
Amino Acid Sequence; Animal; Ascorbic Acid|PD; Cell Fractionation; Chlorides|PD; Ferrous Compounds|PD; Hydrogen-Ion Concentration; Intracellular Membranes|EN; Isoenzymes|CH/IP/ME; Kinetics; Manganese Compounds|PD; Molecular Sequence Data; Molecular Weight; NAD|ME; Organelles|EN; Sequence Analysis; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0166-6851
Country of Publication
NETHERLANDS


Record 15 from database: MEDLINE
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Title
Purification and characterization of a malic enzyme from the ruminal bacterium Streptococcus bovis ATCC 15352 and cloning and sequencing of its gene.
Author
Kawai S; Suzuki H; Yamamoto K; Inui M; Yukawa H; Kumagai H
Address
Department of Food Science and Technology, Faculty of Agriculture, Kyoto University, Japan.
Source
Appl Environ Microbiol, 1996 Aug, 62:8, 2692-700
Abstract
Malic enzyme (EC 1.1.1.39), which catalyzes L-malate oxidative decarboxylation and pyruvate reductive carboxylation, was purified to homogeneity from Streptococcus bovis ATCC 15352, and properties of this enzyme were determined. The 2.9-kb fragment containing the malic enzyme gene was cloned, and the sequence was determined and analyzed. The enzymatic properties of the S. bovis malic enzyme were almost identical to those of other malic enzymes previously reported. However, we found that the S. bovis malic enzyme catalyzed unknown enzymatic reactions, including reduction of 2-oxoisovalerate, reduction of 2-oxoisocaproate, oxidation of D-2-hydroxyisovalerate, and oxidation of D-2-hydroxyisocaproate. The requirement for cations and the optimum pH of these unique activities were different from the requirement for cations and the optimum pH of the L-malate oxidative decarboxylating activity. A sequence analysis of the cloned fragment revealed the presence of two open reading frames that were 1,299 and 1,170 nucleotides long. The 389-amino-acid polypeptide deduced from the 1,170-nucleotide open reading frame was identified as the malic enzyme; this enzyme exhibited high levels of similarity to malic enzymes of Bacillus stearothermophilus and Haemophilus influenzae and was also similar to other malic enzymes and the malolactic enzyme of Lactococcus lactis.
Language of Publication
English
Unique Identifier
96316385

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MeSH Heading (Major)
Malate Dehydrogenase|CH/GE/*IP; Streptococcus bovis|*EN
MeSH Heading
Amino Acid Sequence; Base Sequence; Cloning, Molecular; Enzyme Stability; Hydrogen-Ion Concentration; Keto Acids|ME; Molecular Sequence Data; Molecular Weight; Pyruvates|ME; Sequence Homology, Amino Acid

Publication Type
JOURNAL ARTICLE
ISSN
0099-2240
Country of Publication
UNITED STATES


Record 16 from database: MEDLINE
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Title
Developmental and nutritional regulation of the messenger RNAs for fatty acid synthase, malic enzyme and albumin in the livers of embryonic and newly-hatched chicks.
Author
Morris SM Jr; Winberry LK; Fisch JE; Back DW; Goodridge AG
Address
Source
Mol Cell Biochem, 1984 Sep, 64:1, 63-8
Abstract
The mRNAs for fatty acid synthase and malic enzyme were almost undetectable in total RNA extracted from the livers of 16-day old chick embryos. Both mRNAs increased in abundance between the 16th day of incubation and the day of hatching. In neonates, fatty acid synthase mRNA level was dependent on nutritional status, increasing slowly if the chicks were starved and rapidly if they were fed. The abundance of malic enzyme mRNA decreased in starved neonatal chicks and increased in fed ones. When neonates were first fed and then starved, starvation caused a large decrease in the abundance of both mRNAs. Conversely, feeding, after a period of starvation, resulted in a substantial increase in both mRNAs. The relative abundances of fatty acid synthase and malic enzyme mRNAs correlated positively with relative rates of enzyme synthesis. Thus, nutritional and hormonal regulation of the synthesis of these two 'lipogenic' enzymes is exerted primarily at a pre-translational level. The abundance of albumin mRNA decreased significantly between the 16th day of incubation and the day of hatching but did not change thereafter in fed or starved chicks. The relative stability of albumin mRNA levels after hatching attests to the selectivity of the nutritional regulation of fatty acid synthase and malic enzyme mRNAs. The decrease in albumin mRNA which occurred between 16 days of incubation and hatching contrasts with the increase in albumin mRNA sequences which occurred during late gestation in the fetal rat (20). High levels of albumin in the chick embryo may be related to the lack of an analogue of mammalian alpha-fetoprotein in birds.
Language of Publication
English
Unique Identifier
85036274

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MeSH Heading (Major)
Fatty Acid Synthetase Complex|*GE; Liver|EM/*PH; Malate Dehydrogenase|*GE; Serum Albumin|*GE
MeSH Heading
Animal; Animals, Newborn; Chick Embryo; Chickens|GE; Gene Expression Regulation; RNA|GE; RNA, Messenger|GE; Support, U.S. Gov't, P.H.S.

Publication Type
JOURNAL ARTICLE
ISSN
0300-8177
Country of Publication
NETHERLANDS


Record 17 from database: MEDLINE
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Title
Regulation of the malic enzyme and fatty acid synthase genes in chick embryo hepatocytes in culture: corticosterone and carnitine regulate responsiveness to triiodothyronine.
Author
Roncero C; Goodridge AG
Address
Department of Biochemistry, University of Iowa, Iowa City 52242.
Source
Arch Biochem Biophys, 1992 Jun, 295:2, 258-67
Abstract
Triiodothyronine (T3) added to chick embryo hepatocytes between 20 and 68 h of culture caused a 30- to 40-fold increase in malic enzyme activity. This T3 response decreased as a function of time; after 1 week in culture, a 48-h incubation with T3 had no effect on hepatocyte malic enzyme activity. Neither corticosterone nor carnitine had a significant effect on malic enzyme activity in the absence of T3 at any time or on the response of malic enzyme to T3 during the first 68 h of culture; both stimulated responsiveness to T3 subsequent to 68 h. The effects of corticosterone and carnitine on malic enzyme activity were additive, suggesting different mechanisms. Corticosterone and carnitine regulated abundance of malic enzyme mRNA. For corticosterone, at least, this effect was due to regulation of transcription. Abundance of fatty acid synthase mRNA was also stimulated by T3 in chick embryo hepatocytes in culture, and its responsiveness to T3 decreased with time. Corticosterone and carnitine stimulated responsiveness to T3 at times subsequent to 68 h. Corticosterone had no effect on binding of T3 to nuclear receptors. Intracellular accumulation of long-chain fatty acids or long-chain acyl-CoAs probably did not cause the loss of responsiveness to T3 or the stimulation of that responsiveness by corticosterone or carnitine because adding serum albumin (0.5%) or long-chain fatty acids (0.25-0.5 mM) to the medium was without effect. Corticosterone and carnitine may control the levels of other metabolic intermediates or protein factors which, in turn, regulate the transcriptional response of the lipogenic genes to T3.
Language of Publication
English
Unique Identifier
92264722

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MeSH Heading (Major)
Carnitine|*PH; Corticosterone|*PH; Fatty Acid Synthetase Complex|*GE; Gene Expression Regulation, Enzymologic|*; Liver|EM/*EN; Malate Dehydrogenase|*GE; Triiodothyronine|*PH
MeSH Heading
Actins|GE; Animal; Blotting, Northern; Cells, Cultured; Chick Embryo; Glyceraldehyde-3-Phosphate Dehydrogenases|GE; RNA, Messenger|GE; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.; Transcription, Genetic

Publication Type
JOURNAL ARTICLE
ISSN
0003-9861
Country of Publication
UNITED STATES


Record 18 from database: MEDLINE
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Title
Desaturation of polyunsaturated fatty acids in Mucor circinelloides and the involvement of a novel membrane-bound malic enzyme.
Author
Kendrick A; Ratledge C
Address
Department of Applied Biology, University of Hull, England.
Source
Eur J Biochem, 1992 Oct, 209:2, 667-73
Abstract
1. The component fatty acids of the endogenous phospholipids of microsomal preparations of Mucor, when shaken at 30 degrees C, increased in both chain length and in degree of unsaturation. The net effect was the production of gamma-linolenic acid which, over 2 h, increased from 17% to 32% of total fatty acids present. No further significant changes occurred after this time. 2. The major site for desaturation/elongation reactions was at the sn-2 position of PtdIns. PtdCho and PtdEtn were not implicated. 3. Of numerous metabolites and cofactors added to the microsomes, only malate could prolong the elongation/desaturation reactions for up to 6 h. This effect was shown to be due to a membrane-associated malic enzyme [malate dehydrogenase (decarboxylating) NADP+] with the NADPH produced being used in fatty-acid desaturation. 4. Kinetic analysis of cytosolic and microsomal enzymes [both in 0.1% (mass/vol.) Chaps] could not distinguish between them. However, when the microsomal malic enzyme was dialysed to remove Chaps, it lost 90% of activity, although the cytosolic malic enzyme lost only 20% activity. 5. The structural analogue of malate, tartronic acid, which is an inhibitor of malic enzyme, also inhibited the malate-induced stimulation of fatty-acyl group desaturation and elongation in the microsomal membranes. 6. It is concluded that two distinct malic enzymes exist, one soluble and one membrane bound, with similar active sites. Both have different roles in the production of NADPH, for lipid metabolism. The former will produce NADPH for fatty-acid biosynthesis whilst the latter produces NADPH for fatty-acid desaturation.
Language of Publication
English
Unique Identifier
93049312

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MeSH Heading (Major)
Fatty Acids, Unsaturated|*ME; Malate Dehydrogenase|*ME; Microsomes|*EN; Mucor|*EN
MeSH Heading
Comparative Study; Cytochrome b5|ME; Cytochrome Reductases|ME; Cytosol|EN; Enzyme Stability; Intracellular Membranes|EN; Kinetics; Substrate Specificity; Support, Non-U.S. Gov't; Thermodynamics

Publication Type
JOURNAL ARTICLE
ISSN
0014-2956
Country of Publication
GERMANY


Record 19 from database: MEDLINE
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Title
Simultaneous determination of organic acids and vitamin C in green beans by liquid chromatography.
Author
Vazquez Oderiz ML; Vazquez Blanco ME; Lopez Hernandez J; Simal Lozano J; Romero Rodriguez MA
Address
Universidad de Santiago de Compostela, Facultad de Farmacia, Departmento de QuÆimica AnalÆitica, NutriciÆon y BromatologÆia, La CoruÃna, Spain.
Source
J AOAC Int, 1994 Jul, 77:4, 1056-9
Abstract
A method is described for determining and quantitating organic acids (oxalic, malic, citric, and fumaric) and vitamin C by liquid chromatography with a UV-visible detector that allows simultaneous monitoring at 2 wavelengths. The method was applied to samples of green beans (Phaseolus vulgaris L.). Recoveries were 97.8% for oxalic acid, 98.9% for malic acid, 98.7% for citric acid, 99.2% for fumaric acid, and 98.5% for vitamin C. Method precisions (coefficients of variation) were 1.7% for oxalic acid, 0.8% for malic acid, 0.9% for citric acid, 1.5% for fumaric acid, and 1.2% for vitamin C. Measurement precisions (coefficients of variation) were 1.32% for oxalic acid, 0.33% for malic acid, 0.62% for citric acid, 1.01% for fumaric acid, and 0.39% for vitamin C. Limits of detection were 0.025 mg/mL for oxalic acid, 0.022 mg/mL for malic acid, 0.024 mg/mL for citric acid, 1.0 x 10(-4) mg/mL for fumaric acid, and 2.7 x 10(-4) mg/mL for vitamin C.
Language of Publication
English
Unique Identifier
94348290

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MeSH Heading (Major)
Acids|*AN; Ascorbic Acid|*AN; Chromatography, Liquid|*MT; Legumes|*CH
MeSH Heading
Citrates|AN; Fumarates|AN; Malates|AN; Oxalates|AN; Reproducibility of Results; Sensitivity and Specificity; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
1060-3271
Country of Publication
UNITED STATES


Record 20 from database: MEDLINE
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Title
Apple juice composition: sugar, nonvolatile acid, and phenolic profiles.
Author
Lee HS; Wrolstad RE
Address
Oregon State University, Department of Food Science and Technology, Corvallis 97331.
Source
J Assoc Off Anal Chem, 1988 Jul, 71:4, 789-94
Abstract
Apples from Michigan, Washington, Argentina, Mexico, and New Zealand were processed into juice; the 8 samples included Golden Delicious, Jonathan, Granny Smith, and McIntosh varieties. Liquid chromatography was used for quantitation of sugars (glucose, fructose, sucrose, and sorbitol), nonvolatile acids (malic, quinic, citric, shikimic, and fumaric), and phenolics (chlorogenic acid and hydroxymethylfurfural [HMF]). Other determinations included pH, 0Brix, and L-malic acid. A number of compositional indices for these authentic juices, e.g., chlorogenic acid content, total malic - L-malic difference, and the HMF:chlorogenic ratio, were at variance with recommended standards. The phenolic profile was shown to be particularly influenced by gelatin fining, with peak areas decreasing by as much as 50%. The L-malic:total malic ratio serves as a better index for presence of synthetic malic acid than does the difference between the 2 determinations. No apparent differences in chemical composition could be attributed to geographic origin.
Language of Publication
English
Unique Identifier
88330681

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MeSH Heading (Major)
Beverages|*AN; Carbohydrates|*AN; Fruit|*AN; Phenols|*AN
MeSH Heading
Acids|AN; Chromatography, Liquid; Gelatin|DU; Indicators and Reagents; Malates|AN; Reference Standards; Support, Non-U.S. Gov't; United States

Publication Type
JOURNAL ARTICLE
ISSN
0004-5756
Country of Publication
UNITED STATES


Record 21 from database: MEDLINE
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Title
Derepressed utilization of L-malic acid and succinic acid by mutants of Pachysolen tannophilus.
Author
Harrod CJ; Rodriguez SB; Thornton RJ
Address
Department of Microbiology and Genetics, Massey University, Palmerston North, New Zealand.
Source
J Ind Microbiol Biotechnol, 1997 Jun, 18:6, 379-83
Abstract
Utilization of the tricarboxylic acid (TCA) cycle intermediates, L-malic acid and succinic acid, by the yeast Pachysolen tannophilus is repressed in the presence of glucose. Strains of P. tannophilus containing mutations in two hexokinases and a glucokinase were characterized for growth on glucose plus L-malic acid or succinic acid. Increased specific utilization rates of malic acid and succinic acid in the presence of glucose were observed in mutants containing a lesion in hexokinase A, an enzyme associated with catabolite repression. Such derepressed mutants may have application in winemaking in which utilization of a major grape acid, L-malic acid, is often desirable for acidity reduction.
Language of Publication
English
Unique Identifier
97391261

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MeSH Heading (Major)
Malates|*ME; Saccharomycetales|*ME; Succinates|*ME
MeSH Heading
Glucose|ME; Hydrogen-Ion Concentration; Mutation; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
1367-5435
Country of Publication
ENGLAND


Record 22 from database: MEDLINE
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Title
Production of L-malic acid via biocatalysis employing wild-type and respiratory-deficient yeasts.
Author
Wang X; Gong CS; Tsao GT
Address
Laboratory of Renewable Resources Engineering, Potter Engineering Center, Purdue University, West Lafayette, IN 47907, USA.
Source
Appl Biochem Biotechnol, 1998 Spr, 70-72:, 845-52
Abstract
The yeast Saccharomyces cerevisiae has been used to efficiently produce L-malic acid from fumaric acid. Fumarase is responsible for the reversible conversion of fumaric and L-malic acids in the TCA cycle. To investigate the function of mitochondrial and cytoplasmic fumarase isoenzymes in L-malic acid bioconversion, a wild-type strain and a cytoplasmic respiratory-deficient mutant devoid of functional mitochondria were employed. The mutant strain, which only contained the cytoplasmic fumarase, was still functional in fumaric acid to L-malic acid bioconversion However, its specific conversion rate was much lower (0.20 g/g.h) than that of the wild-type strain (0.55 g/g.h).
Language of Publication
English
Unique Identifier
98290870

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MeSH Heading (Major)
Malates|*CS; Saccharomyces cerevisiae|GE/*ME
MeSH Heading
Catalysis; Cytoplasm|EN; Dyes; Fermentation; Fumarate Hydratase|CH; Fumarates|CH; Mitochondria|EN; Oxygen Consumption|GE; Stereoisomerism; Support, U.S. Gov't, Non-P.H.S.; Tetrazolium Salts

Publication Type
JOURNAL ARTICLE
ISSN
0273-2289
Country of Publication
UNITED STATES


Record 23 from database: MEDLINE
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Title
Molecular analysis of the malic enzyme gene (mae2) of Schizosaccharomyces pombe.
Author
Viljoen M; Subden RE; Krizus A; Van Vuuren HJ
Address
Department of Microbiology, University of Stellenbosch, South Africa.
Source
Yeast, 1994 May, 10:5, 613-24
Abstract
Sequence analysis of a 4.6-kb HindIII fragment containing the malic enzyme gene (mae2) of Schizosaccharomyces pombe, revealed the presence of an open reading frame of 1695 nucleotides, coding for a 565 amino acid polypeptide. The mae2 gene is expressed constitutively and encodes a single mRNA transcript of 2.0 kb. The mae2 gene was mapped on chromosome III by chromoblotting. The coding region and inferred amino acid sequence showed significant homology with 12 malic enzyme genes and proteins from widely different origins. Eight highly homologous regions were found in these malic enzymes, suggesting that they contain functionally conserved amino acid sequences that are indispensable for activity of malic enzymes. Two of these regions have previously been reported to be NAD- and NADP-binding sites.
Language of Publication
English
Unique Identifier
95028159

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MeSH Heading (Major)
Genes, Fungal|*; Malate Dehydrogenase|*GE/ME; Schizosaccharomyces|EN/*GE
MeSH Heading
Amino Acid Sequence; Base Sequence; Blotting, Northern; Chromosome Mapping; DNA Probes; Molecular Sequence Data; NAD; NADP; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0749-503X
Country of Publication
ENGLAND


Record 24 from database: MEDLINE
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Title
Affinity cleavage at the putative metal-binding site of pigeon liver malic enzyme by the Fe(2+)-ascorbate system.
Author
Wei CH; Chou WY; Huang SM; Lin CC; Chang GG
Address
Graduate Institutes of Life Sciences and Biochemistry, National Defense Medical Center, Taipei, Taiwan, Republic of China.
Source
Biochemistry, 1994 Jun, 33:25, 7931-6
Abstract
Pigeon liver malic enzyme was rapidly inactivated by micromolar concentrations of ferrous sulfate in the presence of ascorbate at neutral pH and 0 or 25 degrees C. Omitting the ascorbate or replacing the ferrous ion with manganese ion did not lead to any inactivation. Manganese, magnesium, zinc, cobalt, or calcium ion at 200 molar excess over ferrous ion offered complete protection of the enzyme from Fe(2+)-induced inactivation. Ni2+ provided partial protection, while Ba2+ or imidazole was ineffective in protection. Addition of 4 mM Mn2+ or 5 mM EDTA into a partially modified enzyme stopped further inactivation of the enzyme. Inclusion of substrates (L-malate or NADP+, singly or in combination) in the incubation mixture did not affect the inactivation rate. The enzyme inactivation was demonstrated to be followed by protein cleavage. Native pigeon liver malic enzyme had a subunit M(r) of 65,000. The inactivated enzyme with residual activity of only 0.3% was cleaved into two fragments with M(r) of 31,000 and 34,000, respectively. The cleavage site was identified as the peptide bond between Asp258 and Ile259. Native pigeon liver malic enzyme was blocked at the N-terminus. Cleavage at the putative metal-binding site exposed a new N-terminus, which was identified to be at the 34-kDa fragment containing the C-terminal half of original sequence 259-557. Our results indicated that Fe2+ catalyzed a specific oxidation of pigeon liver malic enzyme at Asp258 and/or some other essential amino acid residues that caused enzyme inactivation. The modified enzyme was then affinity cleaved at the Mn(2+)-binding site.
Language of Publication
English
Unique Identifier
94281225

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MeSH Heading (Major)
Ascorbic Acid|*CH; Ferrous Compounds|*CH; Malate Dehydrogenase|AI/*CH; Manganese|*CH; Metalloproteins|*CH
MeSH Heading
Amino Acid Sequence; Animal; Aspartic Acid|CH; Comparative Study; Liver|EN; Molecular Sequence Data; Pigeons; Sequence Alignment; Sequence Homology, Amino Acid; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0006-2960
Country of Publication
UNITED STATES


Record 25 from database: MEDLINE
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Title
Cloning and expression of pigeon liver cytosolic NADP(+)-dependent malic enzyme cDNA and some of its abortive mutants.
Author
Chou WY; Huang SM; Liu YH; Chang GG
Address
Department of Biochemistry, National Defense Medical Center, Taipei, Taiwan, Republic of China.
Source
Arch Biochem Biophys, 1994 Apr, 310:1, 158-66
Abstract
A full-length 1927-base-pair cDNA of pigeon liver malic enzyme was obtained by utilizing the screening of the cDNA library and polymerase chain reaction techniques. The cDNA contained one open reading frame coding for 557 amino acid residues, flanked by 86 and 167 nucleotides at the 5' and 3' termini, respectively, and was successfully cloned and expressed in Escherichia coli cells. Functionally active recombinant malic enzyme was purified from the cells. This recombinant enzyme has a Km value for L-malate of 160 +/- 30 microM, which is almost identical to that for the natural enzyme (150 +/- 17 microM). The Km value for Mn2+ (4.2 +/- 0.3 microM) is higher than that for the natural pigeon malic enzyme (1.4 +/- 0.2 microM), while the Km value for NADP+ (3.8 +/- 0.3 microM) is lower than that for the natural enzyme (10.8 +/- 0.1 microM). The catalytic constant (kcat) for the recombinant enzyme is decreased by 3.6-fold, but the substrate inhibition constant for L-malate is increased by about 40-fold. Change in the quaternary structure of the recombinant enzyme was revealed in the pH perturbation examination. A truncated pigeon liver malic enzyme, lacking the first 13 amino acid residues, and a recombinant protein, mutated at F19S, N250S, and L353Q, showed no enzymatic activity. Both abortive recombinant mutant proteins were still able to bind with 2',5'-ADP agarose; however, the fluorescence emission spectrum of the protein bound NADPH did not show a blue shift as the natural enzyme. In accordance with these observations, we suggest that the adenosine 2',5'-bisphosphate binding domain of the NADP+ binding site in the beta alpha beta motif may still be retained in these mutant proteins. However, the local hydrophobic environment for the binding of the nicotinamide moiety of the coenzyme molecule may be altered. Therefore, the lack of catalytic activity of the mutant proteins could be attributed to an improper orientation of the bound NADP+.
Language of Publication
English
Unique Identifier
94213482

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MeSH Heading (Major)
Cytosol|*EN; Liver|*EN; Malate Dehydrogenase|*GE/ME
MeSH Heading
Adenosine Diphosphate|ME; Amino Acid Sequence; Animal; Base Sequence; Chromatography, Affinity; Cloning, Molecular; Comparative Study; DNA Probes; DNA, Complementary|GE; Escherichia coli|GE; Gene Library; Molecular Sequence Data; Mutation; NADP|ME; Pigeons; Protein Conformation; Recombinant Proteins|BI; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0003-9861
Country of Publication
UNITED STATES


Record 26 from database: MEDLINE
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Title
Plant mitochondrial NAD+-dependent malic enzyme. cDNA cloning, deduced primary structure of the 59- and 62-kDa subunits, import, gene complexity and expression analysis.
Author
Winning BM; Bourguignon J; Leaver CJ
Address
Department of Plant Sciences, University of Oxford, United Kingdom.
Source
J Biol Chem, 1994 Feb, 269:7, 4780-6
Abstract
The 59- and 62-kDa subunits of the mitochondrial NAD+-dependent malic enzyme (EC 1.1.1.39) were purified from Solanum tuberosum L. (potato). NH2-terminal and internal amino acid sequence information was used to identify cDNAs encoding the two subunits. Comparison of the nucleotide sequences revealed that the subunits have 60% identity at the DNA level and 65% identity at the deduced amino acid level, implying that they are derived from a common ancestral gene. The plant NAD+-dependent malic enzymes belong to a family of related enzymes, including cytosolic and chloroplastic NADP+-dependent malic enzymes (EC 1.1.1.40) and bacterial NAD+-dependent malic enzymes (EC 1.1.1.38). The cDNAs were transcribed and translated in vitro and the resultant polypeptides imported into isolated mitochondria and shown to be processed. Southern blot analysis of potato genomic DNA revealed a simple pattern of hybridization for both subunits, indicating a simple gene structure or small number of genes encoding the two subunits. Northern blot analysis of RNA from a range of potato tissues has shown that the steady state levels for the two subunits are equivalent, suggesting that they are coordinately expressed.
Language of Publication
English
Unique Identifier
94148921

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MeSH Heading (Major)
Gene Expression|*; Malate Dehydrogenase|*BI/*GE/IP; Mitochondria|*EN; Potatoes|*EN/GE
MeSH Heading
Amino Acid Sequence; Animal; Base Sequence; Blotting, Northern; Blotting, Southern; Cloning, Molecular; Comparative Study; DNA|BI/IP; DNA, Complementary|ME; Genes, Plant; Human; Macromolecular Systems; Molecular Sequence Data; NAD|ME; Sequence Homology, Amino Acid; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0021-9258
Country of Publication
UNITED STATES


Record 27 from database: MEDLINE
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Title
Human NAD(+)-dependent mitochondrial malic enzyme. cDNA cloning, primary structure, and expression in Escherichia coli.
Author
Loeber G; Infante AA; Maurer Fogy I; Krystek E; Dworkin MB
Address
Ernst Boehringer Institut, Vienna, Austria.
Source
J Biol Chem, 1991 Feb, 266:5, 3016-21
Abstract
Mitochondrial NAD(+)-dependent malic enzyme (EC 1.1.1.40) is expressed in rapidly proliferating cells and tumor cells, where it is probably linked to the conversion of amino acid carbon to pyruvate. In this paper, we report the cDNA cloning, amino acid sequence, and expression in Escherichia coli of functional human NAD(+)-dependent mitochondrial malic enzyme. The cDNA is 1,923 base pairs long and contains an open reading frame coding for a 584-amino acid protein. The molecular mass is 65.4 kDa for the unprocessed precursor protein. Comparison of the amino acid sequence of the human protein with the published NADP(+)-dependent mammalian cytosolic or plant chloroplast malic enzymes reveals highly conserved regions interrupted with long stretches of amino acids without significant homology. Expression of the processed protein in E. coli yielded an enzyme with the same kinetic and allosteric properties as malic enzyme purified from human cells.
Language of Publication
English
Unique Identifier
91131600

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MeSH Heading (Major)
Escherichia coli|*GE; Gene Expression Regulation, Bacterial|*; Malate Dehydrogenase|*GE; Mitochondria|*EN; NAD|*ME
MeSH Heading
Amino Acid Sequence; Animal; Chromatography, High Pressure Liquid; Cloning, Molecular; DNA|GE; Electrophoresis, Polyacrylamide Gel; Human; Mice; Molecular Sequence Data; Plants|GE; Rats; Sequence Homology, Nucleic Acid; Trypsin

Publication Type
JOURNAL ARTICLE
ISSN
0021-9258
Country of Publication
UNITED STATES


Record 28 from database: MEDLINE
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Title
Nutritional regulation and tissue-specific expression of the malic enzyme gene in the chicken. Transcriptional control and chromatin structure.
Author
Ma XJ; Salati LM; Ash SE; Mitchell DA; Klautky SA; Fantozzi DA; Goodridge AG
Address
Department of Biochemistry, University of Iowa, Iowa City 52242.
Source
J Biol Chem, 1990 Oct, 265:30, 18435-41
Abstract
Refeeding starved chicks causes a 25- to 50-fold increase in the level of malic enzyme mRNA in liver. To define the regulated steps, we measured transcriptional activity of the malic enzyme gene using the nuclear run-on assay and a variety of DNA probes specific to the malic enzyme gene. Refeeding starved chicks stimulated transcription of the malic enzyme gene in liver by 40- to 50-fold. An increased transcription rate was detectable at 1.5 h, was maximal at 3 h, and remained high at 24 h of refeeding. The level of nuclear precursor RNA for malic enzyme assessed by hybridization with intron-specific probes was high in liver of refed birds, and barely detectable in that of starved birds. These results indicate that nutritional regulation of the level of malic enzyme mRNA is transcriptional. Low levels of malic enzyme mRNA in brain, kidney, and heart correlated well with low rates of transcription of the malic enzyme gene in these tissues. In contrast to liver, neither the rate of transcription nor the steady-state level of malic enzyme mRNA was affected by refeeding starved birds. A series of DNase I-hypersensitive sites were located within 4000 base pairs upstream of the transcription start site of the malic enzyme gene in liver. The DNase I-hypersensitive region extending from the start of transcription to 400 base pairs upstream was much more pronounced in the refed state than in the starved state. This change in DNase I hypersensitivity followed the same time course as increased transcription of the malic enzyme gene. This DNase I-hypersensitive region also was present at low intensity in kidney and heart independently of nutritional state. The three constitutive DNase I-hypersensitive sites further upstream were present in liver but not in kidney or heart.
Language of Publication
English
Unique Identifier
91009340

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MeSH Heading (Major)
Chickens|*GE; Chromatin|*UL; Gene Expression Regulation, Enzymologic|*; Malate Dehydrogenase|*GE
MeSH Heading
Animal; Animal Nutrition; Blotting, Northern; Cell Nucleus|ME; Deoxyribonuclease I|PD; DNA|GE; Genes, Structural; Kidney|PH; Liver|PH; Nucleic Acid Precursors|ME; Regulatory Sequences, Nucleic Acid; Restriction Mapping; Support, U.S. Gov't, P.H.S.; Tissue Distribution; Transcription, Genetic

Publication Type
JOURNAL ARTICLE
ISSN
0021-9258
Country of Publication
UNITED STATES


Record 29 from database: MEDLINE
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Title
A simple plate-assay for the screening of L-malic acid producing microorganisms.
Author
Peleg Y; Rokem JS; Goldberg I
Address
Department of Applied Microbiology, Hebrew University-Hadassah Medical School, Jerusalem, Israel.
Source
FEMS Microbiol Lett, 1990 Feb, 55:3, 233-6
Abstract
A simple plate-assay has been developed to screen microorganisms for L-malic acid production. Acid producing organisms were identified, after microbial colony growth on media containing glucose or fumaric acid as sole carbons sources, by formation of a dark halo of formazan. The halo was observed when the plate was covered with a soft agar overlay containing NAD(+)-malate dehydrogenase, NAD+, phenazine methosulfate (PMS) and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT). The assay developed is simple, specific for L-malic acid and therefore can be used to identify L-malic acid producing filamentous fungi using glucose as carbon source (e.g. Aspergillus strains). The assay is also applicable for screening bacteria with high fumarase activity, able to convert fumaric acid to L-malic acid.
Language of Publication
English
Unique Identifier
90215177

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MeSH Heading (Major)
Aspergillus|*ME; Bacteria|*ME; Malates|*ME; Microbiological Techniques|*
MeSH Heading
Culture Media; Fumarates|ME; Isoenzymes; Malate Dehydrogenase

Publication Type
JOURNAL ARTICLE
ISSN
0378-1097
Country of Publication
NETHERLANDS


Record 30 from database: MEDLINE
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Title
L-malic-acid permeation in resting cells of anaerobically grown Saccharomyces cerevisiae.
Author
Salmon JM
Address
Source
Biochim Biophys Acta, 1987 Jul, 901:1, 30-4
Abstract
The study of permeation of L-malic acid in cells of Saccharomyces cerevisiae at pH 3.0 was carried out with (U-14C)-labelled L-malic acid. Resting cells were used in these experiments. They were previously anaerobically grown on glucose. This study showed that this transport is the result of two competitive mechanisms, one for the uptake and one for the efflux. The uptake mechanism seems to be a simple diffusion of the L-malic acid in a non-dissociated form. The efflux mechanism seems to be an active transport of L-malic acid that is very dependent on the temperature. At the steady state, the result of uptake and efflux mechanisms leads to an intracellular concentration which is twice or three times the extracellular concentration.
Language of Publication
English
Unique Identifier
87242453

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MeSH Heading (Major)
Cell Membrane Permeability|*; Malates|*ME; Saccharomyces cerevisiae|*ME
MeSH Heading
Biological Transport|DE; Dicyclohexylcarbodiimide|PD; Dinitrophenols|PD; Kinetics; Temperature

Publication Type
JOURNAL ARTICLE
ISSN
0006-3002
Country of Publication
NETHERLANDS


Record 31 from database: MEDLINE
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Title
The chicken malic enzyme gene: structural organization and identification of triiodothyronine response elements in the 5'-flanking DNA.
Author
Hodnett DW; Fantozzi DA; Thurmond DC; Klautky SA; MacPhee KG; Estrem ST; Xu G; Goodridge AG
Address
Department of Biochemistry, University of Iowa, Iowa City 52242, USA.
Source
Arch Biochem Biophys, 1996 Oct, 334:2, 309-24
Abstract
In vivo, feeding stimulates and starvation inhibits transcription of the malic enzyme gene. In chick-embryo hepatocytes in culture, triiodothyronine (T3) stimulates and glucagon inhibits transcription of this gene. As a first step in the characterization of the involved regulatory mechanisms, fragments of genomic DNA spanning the structural and 5'-flanking regions of the chicken malic enzyme gene were cloned. The coding region of the gene is organized into 14 exons and 13 introns and is greater than 106 kb in length. The size of the gene, the number and lengths of the exons, and positions at which introns are inserted into the coding regions are virtually identical in the chicken and rat genes. When transiently transfected into chick-embryo hepatocytes, 5800 bp of 5'-flanking DNA conferred T3 responsiveness to a linked chloramphenicol acetyltransferase (CAT) reporter gene. Using deletion and site-specific mutations of 5'-flanking DNA, we identified a complex T3 response unit that contains one major T3 response element (T3RE) and several minor ones. The major element contains two degenerate copies of the hexamer, RGGWMA, separated by 4 bp and was a strong repressor in the absence of ligand. Endogenous levels of T3 receptor are sufficient to allow the T3 response elements in the upstream region of the malic enzyme gene to confer responsiveness to T3, suggesting that they are physiologically relevant.
Language of Publication
English
Unique Identifier
97056061

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MeSH Heading (Major)
Chickens|*GE; Malate Dehydrogenase|*BI/*GE; Regulatory Sequences, Nucleic Acid|*/DE; Triiodothyronine|*PD
MeSH Heading
Animal; Base Sequence; Cells, Cultured; Chick Embryo; Chloramphenicol O-Acetyltransferase|BI; Liver|ME; Molecular Sequence Data; Mutagenesis, Site-Directed; Rats; Recombinant Fusion Proteins|BI; Repetitive Sequences, Nucleic Acid; Restriction Mapping; Sequence Deletion; Sequence Homology, Nucleic Acid; Support, U.S. Gov't, P.H.S.; Transfection

Publication Type
JOURNAL ARTICLE
ISSN
0003-9861
Country of Publication
UNITED STATES


Record 32 from database: MEDLINE
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Title
Sequence of a malic enzyme gene of Giardia lamblia.
Author
Sánchez LB; Hashimoto T; Müller M
Address
Rockefeller University, New York, NY 10021, USA. sanchel@rockvax.rockefeller.edu
Source
Mol Biochem Parasitol, 1996 Nov, 82:2, 145-51
Abstract
The nucleotide sequence and predicted amino acid sequence of malate dehydrogenase (decarboxylating) or malic enzyme (EC 1.1.1.40) of the amitochondriate protist Giardia lamblia were determined. The overall amino acid identity with malic enzyme sequences from other eukaryotes was between 34 and 39%. Functional domains previously defined in other malic enzymes, the malate-, the ADP- and the NAD(P)-binding domains, were present also in the G. lamblia sequence. In phylogenetic reconstructions, the G. lamblia sequence is part of the eukaryotic clade, but its relative position versus the other early branches of the eukaryotic tree (Trichomonas vaginalis hydrogenosome and plant mitochondria) cannot be firmly established. The results indicate, however, a long, independent evolutionary past of this enzyme.
Language of Publication
English
Unique Identifier
97101863

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MeSH Heading (Major)
Genes, Protozoan|*; Giardia lamblia|EN/*GE; Malate Dehydrogenase|CL/*GE
MeSH Heading
Amino Acid Sequence; Animal; Binding Sites; Comparative Study; Evolution, Molecular; Likelihood Functions; Molecular Sequence Data; Phylogeny; Sequence Analysis; Sequence Homology, Amino Acid; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.

Publication Type
JOURNAL ARTICLE
ISSN
0166-6851
Country of Publication
NETHERLANDS


Record 33 from database: MEDLINE
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Title
Swine cytosolic malic enzyme: cDNA cloning, sequencing, and localization.
Author
Nunes M; Lahbib Mansais Y; Geffrotin C; Yerle M; Vaiman M; Renard C
Address
Laboratoire mixte INRA-CEA de Radiobiologie appliquÆee, centre de recherche INRA de Jouy-en-Josas, 78352 France.
Source
Mamm Genome, 1996 Nov, 7:11, 815-21
Abstract
A highly significant genetic association has been found between some alleles of the swine Major Histocompatibility Complex SLA (Swine Leukocyte Antigen genetic complex) and the cytosolic malic enzymatic activity level in muscles. The aim of this study was to find out whether this genetic association was due to a close linkage of the SLA region and the gene coding for the enzyme. Since no swine cytosolic malic enzyme sequence (ME1) was available, we isolated several overlapping fragments that spanned the almost entire malic enzyme transcript both by screening of a swine cDNA library and by RT-PCR. The results indicated the existence of two transcripts of 2. 0 and 3.1 kb, which probably correspond to two alternative forms of one gene. The sequence of the transcript was highly similar to the other published mammalian cytosolic NADP+-dependent malic enzyme cDNA, especially within the four functional domains. Two major bands at 3.7 and 2.4 kb were detected on Northern blots containing the RNA from 25 tissues from fetuses and adult pigs. A high expression level was found in the adrenal gland, muscle, liver, and peripheral nerves. The analysis of malic enzyme RFLPs in five SLA informative families revealed an independent segregation of the ME1 gene from the SLA region. In situ hybridization results localized the cytosolic malic enzyme on the swine Chromosome (Chr) 1p1.2, except that the association between SLA and the malic enzyme activity level was due to a physical genetic linkage. Thus, the mechanisms underlying this association remain to be elucidated.
Language of Publication
English
Unique Identifier
97032530

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MeSH Heading (Major)
Chromosome Mapping|*; Malate Dehydrogenase|BI/*CH/*GE; Swine|*GE
MeSH Heading
Amino Acid Sequence; Animal; Base Sequence; Cloning, Molecular; Comparative Study; Cytosol; DNA Primers; DNA Probes; DNA, Complementary; Female; Human; Male; Mitochondria|EN; Molecular Sequence Data; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Rats; Restriction Mapping; Sequence Homology, Amino Acid

Publication Type
JOURNAL ARTICLE
ISSN
0938-8990
Country of Publication
UNITED STATES


Record 34 from database: MEDLINE
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Title
Nonidentity of the cDNA sequence of human breast cancer cell malic enzyme to that from the normal human cell.
Author
Chou WY; Huang SM; Chang GG
Address
Department of Biochemistry, National Defense Medical Center, Taipei, Taiwan, Republic of China.
Source
J Protein Chem, 1996 Apr, 15:3, 273-9
Abstract
A cDNA coding for human breast cancer cell cytosolic NADP(+)-dependent malic enzyme was obtained. This cDNA is composed of a length of 2084 base pairs, with 1698 base pairs coding for 565 amino acid residues and a length of 386 base pairs representing a 3'-noncoding region. Comparing this nucleotide sequence with that from the normal human tissue [Loeber, G., Dworkin, M. B., Infante, A., and Ahorn, H. (1994), FEBS Lett. 344, 181-186] reveals that three nucleotides in the open reading frame and the length of 3'-noncoding region of the cDNA are different. One of the changes results in a substitution of serine at position 438 for proline, which, however, may not cause significant changes in the predicted secondary structure. A partial cDNA lacking the first 84 nucleotides in the open reading frame was successfully cloned and expressed functionally in Escherichia coli cells. Its Km value for L-malate (1.21 +/- 0.11 mM) is four times higher than that for the natural human breast cancer cell malic enzyme (0.29 +/- 0.04 mM) but similar to that for the full-length recombinant enzyme (1.06 +/- 0.07 mM). The Km values for Mn2+ and NADP+ (0.26 +/- 0.03 and 0.97 +/- 0.4 microM, respectively) are similar to those for the natural enzyme (0.12 +/- 0.02 and 1.9 +/- 0.3 microM, respectively) or the recombinant wild-type enzyme (0.56 +/- 0.04 and 0.44 +/- 0.02 microM, respectively). A recombinant pigeon liver malic enzyme without the first 13 amino acid residues was used for comparison. The Km values for L-malate and Mn2+ of the truncated enzyme (11.2 +/- 0.9 mM and 61.2 +/- 4.6 microM, respectively) are over 40 times larger than those for the natural pigeon liver malic enzyme (0.21 +/- 0.02 mM and 1.06 +/- 0.08 microM, respectively) or the recombinant wild-type enzyme (0.25 +/- 0.01 mM and 1.48 +/- 0.05 microM, respectively). We suggest that the N-terminus of malic enzyme may be required for the substrate binding during the catalytic cycle.
Language of Publication
English
Unique Identifier
96397682

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MeSH Heading (Major)
Breast Neoplasms|*EN/PA; Malate Dehydrogenase|CH/*GE/IP/ME
MeSH Heading
Amino Acid Sequence; Animal; Base Sequence; Blotting, Northern; Cloning, Molecular; Comparative Study; Cytosol|CH/EN; DNA Probes; DNA, Complementary|CH; DNA, Neoplasm|CH; Female; Human; Kinetics; Mice; Molecular Sequence Data; Pigeons; Plasmids; Rats; Recombinant Proteins|CH/GE/IP/ME; RNA, Neoplasm|AN/GE; Sequence Alignment; Sequence Analysis, DNA; Support, Non-U.S. Gov't; Tumor Cells, Cultured

Publication Type
JOURNAL ARTICLE
ISSN
0277-8033
Country of Publication
UNITED STATES


Record 35 from database: MEDLINE
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Title
Overexpression of the alpha-thyroid hormone receptor in avian cell lines. Effects on expression of the malic enzyme gene are selective and cell-specific.
Author
Hillgartner FB; Chen W; Goodridge AG
Address
Department of Biochemistry, University of Iowa, Iowa City 52242.
Source
J Biol Chem, 1992 Jun, 267:17, 12299-306
Abstract
The role of the alpha-thyroid hormone receptor (TR alpha) in regulation of transcription of the gene for chicken malic enzyme was analyzed in fibroblast cell lines normally unresponsive to triiodothyronine (T3). The gene for this transcription factor was introduced stably and overexpressed using a replication-competent retroviral vector. In chick embryo fibroblasts (CEF), overexpression of TR alpha decreased malic enzyme activity by 90% in the absence of T3. Addition of T3 almost completely restored malic enzyme activity to the level of similarly treated control CEF infected with virus lacking TR alpha. These TR alpha-induced changes in malic enzyme activity were mediated by alterations in transcription of the malic enzyme gene. Similar results were obtained when transcriptional activity of TR alpha was analyzed using a transient co-transfection system. Thus, the unliganded TR alpha is a transcriptional repressor of the malic enzyme gene; binding of T3 to the receptor abolishes this repression. In contrast, stable overexpression of TR alpha in QT6 cells had no effect on malic enzyme expression in the absence or presence of T3. Nuclear T3 binding was equally high in CEF and QT6 cells overexpressing TR alpha. These findings suggest that cell-specific factors control the ability of TR alpha to regulate the malic enzyme gene. Overexpression of TR alpha in CEF had no effect on the expression of fatty acid synthase and acetyl-CoA carboxylase, lipogenic enzymes that are stimulated by T3 in hepatocytes in culture. Thus, gene-specific factors also may control the transcriptional activity of TR alpha.
Language of Publication
English
Unique Identifier
92291117

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MeSH Heading (Major)
Gene Expression Regulation, Enzymologic|*; Malate Dehydrogenase|*GE; Receptors, Thyroid Hormone|GE/*PH
MeSH Heading
Acetyl-CoA Carboxylase|GE; Actins|GE; Animal; Cell Line; Chick Embryo; DNA Probes; Fatty Acid Synthetase Complex|GE; Fibroblasts|EN; Glyceraldehyde-3-Phosphate Dehydrogenases|GE; Proto-Oncogene Proteins|GE; RNA, Messenger|ME; Support, U.S. Gov't, P.H.S.; Transcription, Genetic; Triiodothyronine|ME

Publication Type
JOURNAL ARTICLE
ISSN
0021-9258
Country of Publication
UNITED STATES


Record 36 from database: MEDLINE
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Title
Triiodothyronine-induced accumulations of malic enzyme, fatty acid synthase, acetyl-coenzyme A carboxylase, and their mRNAs are blocked by protein kinase inhibitors. Transcription is the affected step.
Author
Swierczynski J; Mitchell DA; Reinhold DS; Salati LM; Stapleton SR; Klautky SA; Struve AE; Goodridge AG
Address
Department of Biochemistry, University of Iowa, Iowa City 52242.
Source
J Biol Chem, 1991 Sep, 266:26, 17459-66
Abstract
Addition of triiodothyronine (T3) to chick-embryo hepatocytes in culture causes increased accumulations of malic enzyme, fatty acid synthase, acetyl-CoA carboxylase and their mRNAs. H-8 and other protein kinase inhibitors inhibited the T3-induced accumulations of these lipogenic enzymes and their mRNAs but had no effect on the activities of 6-phosphogluconate dehydrogenase and isocitrate dehydrogenase, enzymes not induced by T3 in chick-embryo hepatocytes. H-8 also had no effect on the activities of malic enzyme, fatty acid synthase, and acetyl-CoA carboxylase in hepatocytes not treated with T3. Synthesis of soluble protein, levels of mRNAs for beta-actin and glyceraldehyde-3-phosphate dehydrogenase, and induction of metallothionein mRNA by Zn2+ were unaffected by H-8 at concentrations that inhibited the T3-induced accumulation of lipogenic enzymes and their mRNAs. H-8 inhibited T3-induced transcription of the genes for both malic enzyme and fatty acid synthase but had little effect on transcription of the beta-actin or glyceraldehyde-3-phosphate dehydrogenase genes or on total RNA synthesis in isolated nuclei. H-8 also had no effect on binding of T3 to its nuclear receptor. In isolated nuclei, H-8 inhibited phosphorylation of total protein by 15-20%. Phosphorylation of only one major protein was consistently and substantially inhibited, indicating that the effect of H-8 was selective. These results suggest that on-going protein phosphorylation is required specifically for stimulation of transcription of the lipogenic genes by T3.
Language of Publication
English
Unique Identifier
91373369

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MeSH Heading (Major)
Acetyl-CoA Carboxylase|GE/*ME; Fatty Acid Synthetase Complex|GE/*ME; Malate Dehydrogenase|GE/*ME; Protein Kinases|*AI; Transcription, Genetic|*DE; Triiodothyronine|*AI/PD
MeSH Heading
Alkaloids|PD; Animal; Cells, Cultured; Chick Embryo; Isoquinolines|PD; Liver|EN; Metallothionein|GE; RNA, Messenger|ME; Support, U.S. Gov't, P.H.S.

Publication Type
JOURNAL ARTICLE
ISSN
0021-9258
Country of Publication
UNITED STATES


Record 37 from database: MEDLINE
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Title
Primary structure of the maize NADP-dependent malic enzyme.
Author
Rothermel BA; Nelson T
Address
Biology Department, Yale University, New Haven, Connecticut 06511.
Source
J Biol Chem, 1989 Nov, 264:33, 19587-92
Abstract
Chloroplast-localized NADP-dependent malic enzyme (EC 1.1.1.40) (NADP-ME) provides a key activity for the carbon 4 fixation pathway. In maize, nuclear encoded NADP-ME is synthesized in the cytoplasm as a precursor with a transit peptide that is removed upon transport into the chloroplast stroma. We present here the complete nucleotide sequence for a 2184-base pair full-length maize NADP-ME cDNA. The predicted precursor protein is 636 amino acids long with a Mr of 69,800. There is a strong codon bias found in the amino-terminal portion of NADP-ME that is present in genes for the other enzymes of the C-4 photosynthetic pathway. The NADP-ME transit peptide has general features common to other known chloroplast stroma transit peptides. Comparison of mature maize NADP-ME to the amino acid sequences of known malic enzymes shows two conserved dinucleotide-binding sites. There is a third highly conserved region of unknown function. On the basis of amino acid sequence similarity, the maize chloroplastic enzyme is more closely related to eukaryotic cytosolic isoforms of malic enzyme than to prokaryotic isoforms. We discuss the functional and evolutionary relationship between the chloroplastic and cytosolic forms of NADP-ME.
Language of Publication
English
Unique Identifier
90062054

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MeSH Heading (Major)
Malate Dehydrogenase|*GE; Plants|*EN/GE
MeSH Heading
Amino Acid Sequence; Animal; Base Sequence; Chloroplasts|EN; Comparative Study; Corn|EN/GE; DNA|GE; Genes, Structural, Plant; Mice; Molecular Sequence Data; Rats; Restriction Mapping; Sequence Homology, Nucleic Acid; Support, U.S. Gov't, P.H.S.

Publication Type
JOURNAL ARTICLE
ISSN
0021-9258
Country of Publication
UNITED STATES


Record 38 from database: MEDLINE
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Title
Tolerance of acid-adapted and non-adapted Escherichia coli O157:H7 cells to reduced pH as affected by type of acidulant.
Author
Deng Y; Ryu JH; Beuchat LR
Address
Department of Food Science and Technology, University of Georgia, Griffin 30223-1797, USA.
Source
J Appl Microbiol, 1999 Feb, 86:2, 203-10
Abstract
A study was carried out to determine if three strains of Escherichia coli O157:H7 grown (18 h) in Tryptic Soy Broth (TSB) and TSB supplemented with 1.25% glucose (TSBG), i.e. unadapted and acid-adapted cells, respectively, exhibited changes in tolerance to reduced pH when plated on Tryptic Soy Agar (TSA) acidified (pH 3.9, 4.2, 4.5, 4.8, 5.1 and 5.4) with acetic, citric or malic acids. All test strains grew well on TSA acidified with acetic acid at pH > or = 5.4 or malic acid at pH > or = 4.5; two strains grew on TSA acidified with citric acid at pH > or = 4.5, while the third strain grew at pH > or = 4.8. Acid-adapted and control (unadapted) cells differed little in their ability to form visible colonies on TSA containing the same acid at the same pH. However, on plates not showing visible colonies, acid-adapted cells retained higher viability than unadapted cells when plated on acidified TSA. Growth of acid-adapted and control cells of E. coli O157:H7 inoculated into TSB containing acetic acid (pH 5.4 and 5.7) and citric or malic acids (pH 4.2 and 4.5) was also studied. There was essentially no difference in growth characteristics of the two types of cells in TSB acidified at the same pH with a given acid. Tolerance of acid-adapted and control cells on subsequent exposure to low pH is influenced by the type of acidulant. The order of sensitivity at a given pH is acetic > citric > malic acid. When performing acid challenge studies to determine survival and growth characteristics of E. coli O157:H7 in foods, consideration should be given to the type of acid to which cells have been exposed previously, the procedure used to achieve acidic environments and possible differences in response among strains. The use of strains less affected by pH than type of acidulant or vice versa could result in an underestimation of the potential for survival and growth of E. coli O157:H7 in acid foods.
Language of Publication
English
Unique Identifier
99163105

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MeSH Heading (Major)
Acids, Acyclic|*PD; Adaptation, Physiological|*DE; Escherichia coli O157|*GD/IP
MeSH Heading
Animal; Cattle; Culture Media; Feces|MI; Food Microbiology; Human; Hydrogen-Ion Concentration; Meat Products|MI

Publication Type
JOURNAL ARTICLE
ISSN
1364-5072
Country of Publication
ENGLAND


Record 39 from database: MEDLINE
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Title
Effects of dentin surface treatments on the shear bond strength of Vitrabond.
Author
Prati C; Montanari G; Biagini G; Fava F; Pashley DH
Address
School of Dentistry, Medical College of Georgia.
Source
Dent Mater, 1992 Jan, 8:1, 21-6
Abstract
The influences of nine dentin surface treatments were evaluated on the shear bond strength of a new light-cured glass-ionomer cement (GIC) and on the SEM morphology of the treated dentin surfaces. The following treatments were performed: saline solution (control), NaOCl, acidic glycine, EDTA, malic acid, malic acid plus glycine, polyacrylic acid, tannic acid, and neutral+acidic oxalate solutions. Buccal dentin surfaces were polished with #320-grit abrasive paper, treated with one of the chemicals, washed, and air-dried. Cylindrical GIC samples were then applied to the dentin surface, stored in 100% humidity, and tested after 24 h. SEM observations demonstrated no effect of saline or NaOCl treatment on the smear layer but its complete removal with exposure of collagen fibrils after malic or malic acid plus glycine treatment. Partial removal of the smear layer occurred following glycine treatment and with tannic or polyacrylic acids. Complete removal of the smear layer was seen after EDTA or pyruvic acid treatment. Oxalate treatment produced a layer of crystals, which completely covered the dentin surface. Shear bond strength of GIC was significantly increased only by treatment with the oxalate solutions.
Language of Publication
English
Unique Identifier
92394372

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MeSH Heading (Major)
Dental Bonding|*; Dentin|*/DE; Glass Ionomer Cements|*CH
MeSH Heading
Comparative Study; Materials Testing; Microscopy, Electron, Scanning; Support, U.S. Gov't, Non-P.H.S.; Support, U.S. Gov't, P.H.S.; Surface Properties; Surface-Active Agents|PD; Tensile Strength

Publication Type
JOURNAL ARTICLE
ISSN
0109-5641
Country of Publication
DENMARK


Record 40 from database: MEDLINE
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Title
Terminal differentiation in the avian uropygial gland. Accumulation of fatty acid synthase and malic enzyme in non-dividing cells.
Author
Jenik RA; Fisch JE; Goodridge AG
Address
Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106.
Source
Cell Tissue Res, 1987 Nov, 250:2, 315-21
Abstract
The secretory tissue of the uropygial gland is of the holocrine type, containing both dividing progenitor cells and lipid-filled differentiated cells. In this study, we examined the relationship between cell division and differentiation. The location of dividing cells was determined by autoradiography of tissue sections from ducklings injected intra-abdominally with 3H-thymidine. Only cells on the basal lamina of the tubules contained labeled nuclei. Dividing cells were distributed uniformly over the length of the tubules. Over the next five days, most of the labeled cells migrated to the lumen of the tubules and disappeared. Cells containing the "lipogenic" enzymes, fatty acid synthase and malic enzyme, were localized either immunocytochemically using affinity-purified antibodies or cytochemically using a specific assay for malic enzyme activity. Fatty acid synthase and malic enzyme were undetectable in dividing basal cells but present at high levels in differentiating and differentiated cells. Thus, basal cells lying along the basal lamina of the tubules were replacing lipid-laden cells that were continually sloughed into the lumens of the tubules. The signals for differentiation and enzyme accumulation appear to be linked to one another and to cessation of cell division.
Language of Publication
English
Unique Identifier
88109475

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MeSH Heading (Major)
Fatty Acid Synthetase Complex|*ME; Malate Dehydrogenase|*ME; Sebaceous Glands|CY/EN/*GD
MeSH Heading
Aging; Animal; Cell Differentiation; Cell Division; Ducks; DNA Replication; Grooming; Kinetics; Support, U.S. Gov't, P.H.S.

Publication Type
JOURNAL ARTICLE
ISSN
0302-766X
Country of Publication
GERMANY, WEST


Record 41 from database: MEDLINE
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Title
D-Malic enzyme of Pseudomonas fluorescens.
Author
Knichel W; Radler F
Address
Source
Eur J Biochem, 1982 Apr, 123:3, 547-52
Abstract
By the enrichment culture technique 14 gram-negative bacteria and two yeast strains were isolated that used D(+)-malic acid as sole carbon source. The bacteria were identified as Pseudomonas putida, Pseudomonas fluorescens, Pseudomonas aeruginosa and Klebsiella aerogenes. In cell-free extracts of P. fluorescens and P. putida the presence of malate dehydrogenase, D-malic enzyme (NAD-dependent) and L-malic enzyme (NADP-dependent) was demonstrated. D-Malic enzyme from P. fluorescens was purified. Stabilization of the enzyme by 50 mM ammonium sulphate an 1 mM EDTA was essential. Preparation of D-malic enzyme that gave one band with disc gel electrophoresis showed a specific activity of 4-5 U/mg. D-Malic enzyme requires divalent cations. The Km values were for malate Km = 0.3 mM and for NAD Km = 0.08 mM. The pH optimum for the reaction was found to be in the range of pH 8.1 to pH 8.8. D-Malic enzyme is partially inhibited by oxaloacetic acid, meso-tartaric acid, D-lactic acid and ATP. Determined by gel filtration and gradient gel electrophoresis, the molecular weight was approximately 175 000.
Language of Publication
English
Unique Identifier
82186730

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MeSH Heading (Major)
Malate Dehydrogenase|*IP; Pseudomonas fluorescens|*EN
MeSH Heading
Cell-Free System; Electrophoresis, Polyacrylamide Gel; Kinetics; Klebsiella pneumoniae|EN; Molecular Weight; Pseudomonas|EN

Publication Type
JOURNAL ARTICLE
ISSN
0014-2956
Country of Publication
GERMANY, WEST


Record 42 from database: MEDLINE
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Title
Role of NADP+ (corrected)-linked malic enzymes as regulators of the pool size of tricarboxylic acid-cycle intermediates in the perfused rat heart [published erratum appears in Biochem J 1987 Aug 1:245(3):following 934]
Author
Sundqvist KE; Heikkilä J; Hassinen IE; Hiltunen JK
Address
Department of Medical Biochemistry, University of Oulu, Finland.
Source
Biochem J, 1987 May, 243:3, 853-7
Abstract
Cytosolic and mitochondrial concentrations of malate, 2-oxoglutarate, isocitrate and pyruvate in the isolated perfused rat heart were measured by non-aqueous tissue fractionation, taking the NADP-linked isocitrate dehydrogenase as indicator reactions for the free [NADPH]/[NADP+] ratios. The mass-action ratios of NADP-linked malic enzymes (EC 1.1.1.40) were found to be on the side of pyruvate carboxylation by more than one order of magnitude in both the cytosolic and the mitochondrial spaces in hearts perfused with glucose, whereas during propionate perfusion this ratio approached the equilibrium constant (Keq.) of malic enzyme. The results consequently indicate that the NADP-linked malic enzymes cannot be responsible for the feed-out (cataplerotic) reactions from the tricarboxylic acid cycle which occur during glucose perfusion. Only when other anaplerotic fluxes into the cycle are high, as during propionate oxidation, which results in accumulation of tricarboxylic acid-cycle intermediates, is a steady state reached which allows efflux via the malic enzyme.
Language of Publication
English
Unique Identifier
88023948

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MeSH Heading (Major)
Citric Acid Cycle|*; Malate Dehydrogenase|*ME; Myocardium|*ME; NADP|*ME
MeSH Heading
Animal; Cell Compartmentation; Female; Oxidation-Reduction; Perfusion; Rats; Rats, Inbred Strains; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0264-6021
Country of Publication
ENGLAND


Record 43 from database: MEDLINE
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Title
Chimeric structure of the NAD(P)+- and NADP+-dependent malic enzymes of Rhizobium (Sinorhizobium) meliloti.
Author
Mitsch MJ; Voegele RT; Cowie A; Osteras M; Finan TM
Address
Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada.
Source
J Biol Chem, 1998 Apr, 273:15, 9330-6
Abstract
Malic enzymes catalyze the oxidative decarboxylation of malate to pyruvate in conjunction with the reduction of a nicotinamide cofactor. We determined the DNA sequence and transcriptional start sites of the genes encoding the diphosphopyridine nucleotide-dependent malic enzyme (DME, EC 1.1.1.39) and the triphosphopyridine nucleotide-dependent malic enzyme (TME, EC 1.1.1. 40) of Rhizobium (Sinorhizobium) meliloti. The predicted DME and TME proteins contain 770 and 764 amino acids, respectively, and are approximately 320 amino acids larger than previously characterized prokaryotic malic enzymes. The increased size of DME and TME resides in the C-terminal extensions which are similar in sequence to phosphotransacetylase enzymes (EC 2.3.1.8). Modified DME and TME proteins which lack this C-terminal region retain malic enzyme activity but are unable to oligomerize into the native state. Data base searches have revealed that similar chimeric malic enzymes were uniquely present in Gram-negative bacteria. Thus DME and TME appear to be members of a new class of malic enzyme characterized by the presence of a phosphotransacetylase-like domain at the C terminus of the protein.
Language of Publication
English
Unique Identifier
98204936

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MeSH Heading (Major)
Evolution, Molecular|*; Malate Dehydrogenase|*CH/*GE/ME; Rhizobium meliloti|*EN/GE
MeSH Heading
Amino Acid Sequence; Bacteria|EN/GE; Chimeric Proteins|BI/CH/ME; Comparative Study; Molecular Sequence Data; Phylogeny; Sequence Alignment; Sequence Homology, Amino Acid; Software; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0021-9258
Country of Publication
UNITED STATES


Record 44 from database: MEDLINE
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Title
Coding nucleotide sequence of rat liver malic enzyme mRNA.
Author
Magnuson MA; Morioka H; Tecce MF; Nikodem VM
Address
Source
J Biol Chem, 1986 Jan, 261:3, 1183-6
Abstract
The nucleotide sequence of the mRNA for malic enzyme ((S)-malate NADP+ oxidoreductase (oxaloacetate-decarboxylating, EC 1.1.1.40) from rat liver was determined from three overlapping cDNA clones. Together, these clones contain 2078 nucleotides complementary to rat liver malic enzyme mRNA. The single open reading frame of 1761 nucleotides codes for a 585-amino acid polypeptide with a calculated molecular mass of about 65,460 daltons. The cloned cDNAs contain the complete 3'-noncoding region of 301 nucleotides for the major mRNA species of rat liver and 16 nucleotides of the 5'-noncoding region. Amino acid sequences of seven tryptic peptides (67 amino acids) from the purified protein are distributed through the single open reading frame and show excellent correspondence with the translated nucleotide sequence. The putative NADP-binding site for malic enzyme was identified by amino acid sequence homology with the NADP-binding site of the enoyl reductase domain of fatty acid synthetase.
Language of Publication
English
Unique Identifier
86111756

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MeSH Heading (Major)
Malate Dehydrogenase|*GE/ME; RNA, Messenger|*AN
MeSH Heading
Amino Acid Sequence; Animal; Base Sequence; Binding Sites; Cloning, Molecular; DNA|AN; Liver|EN; Molecular Weight; NADP|ME; Peptide Fragments|AN; Rats; Trypsin|ME

Publication Type
JOURNAL ARTICLE
ISSN
0021-9258
Country of Publication
UNITED STATES


Record 45 from database: MEDLINE
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Title
Effects of grinding and humidification on the transformation of conglomerate to racemic compound in optically active drugs.
Author
Piyarom S; Yonemochi E; Oguchi T; Yamamoto K
Address
Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Chiba University, Japan.
Source
J Pharm Pharmacol, 1997 Apr, 49:4, 384-9
Abstract
The effects of grinding and humidification on the transformation of conglomerate to racemic compound have been investigated by X-ray powder diffraction (XPD), differential scanning calorimetry (DSC) and infrared (IR) spectroscopy for leucine, norleucine, valine, serine, tartaric acid and malic acid. Racemic physical mixtures were prepared by physical mixing of equimolar quantities of D and I. crystals using a mortar and pestle. Ground mixtures were obtained by grinding the physical mixtures with a vibrational mill. Humidification was performed by storing the physical mixtures and the ground mixtures in a desiccator containing saturated aqueous salt solutions at 40 degrees C. When physical mixtures of malic acid, tartaric acid and serine were ground, the XPD peaks of the racemic compounds were observed. The XPD patterns of humidified physical mixtures of these compounds also showed the formation of the racemic compounds. This indicated that grinding or humidification of malic acid, tartaric acid and serine induced the transformation of conglomerate to racemic compound crystals. When, on the other hand, the physical mixtures of valine, leucine and norleucine were ground, peaks of racemic compounds were not detected in the XPD pattern. After humidification of the ground mixtures of valine, leucine and norleucine, however, the XPD peaks of racemic compounds were observed. DSC and IR studies revealed consistent results. We concluded that grinding or humidification of malic acid, tartaric acid and serine could induce the transformation of a conglomerate to racemic compound. In contrast, humidifying after grinding was needed to bring about the transformation in leucine, norleucine and valine.
Language of Publication
English
Unique Identifier
97376425

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MeSH Heading (Major)
Leucine|*CH; Malates|*CH; Norleucine|*CH; Serine|*CH; Tartrates|*CH; Valine|*CH
MeSH Heading
Calorimetry, Differential Scanning; Humidity; Optical Rotation; Reference Standards; Spectrophotometry, Infrared; Stereoisomerism; Support, Non-U.S. Gov't; Temperature; X-Ray Diffraction

Publication Type
JOURNAL ARTICLE
ISSN
0022-3573
Country of Publication
ENGLAND


Record 46 from database: MEDLINE
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Title
The distribution of six enzymes of oxidative metabolism along the rat nephron.
Author
Burch HB; Bross TE; Brooks CA; Cole BR; Lowry OH
Address
Source
J Histochem Cytochem, 1984 Jul, 32:7, 731-6
Abstract
Using quantitative methods, citrate synthase (CS), fumarase, beta-hydroxyacyl-coenzyme A (CoA) dehydrogenase (beta OAC), 3-keto-acid CoA transferase (KCT), malic dehydrogenase (MDH), and malic enzyme were measured in seven defined parts of the nephron and in thin limb and papilla areas dissected from freeze-dried microtome sections of rat kidney. The results not only show a wide range of activity along the nephron for each of the enzymes, but that the proportions between the enzymes vary markedly among the different parts of the nephron. This suggests the existence of major regional differences in the capacity to oxidize specific metabolites. The ratio between two citrate cycle enzymes, fumarase and CS, was 4- or 5-fold higher in proximal segments than in the glomerulus or thin limb areas. The ratio between beta OAC (an enzyme of fatty acid oxidation) and CS was 3- to 5-fold higher in the middle proximal segments than in glomeruli or thin limb and papilla areas. The key enzyme for ketone body metabolism, KCT, was essentially confined to the thick tubule segments. Malic enzyme, in contrast to the other five enzymes, was highest in the proximal straight segments. New methods, sufficiently sensitive for this histochemical study, are described for malic enzyme and 3-keto-acid CoA transferase.
Language of Publication
English
Unique Identifier
84241023

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MeSH Heading (Major)
Citric Acid Cycle|*; Nephrons|*EN/UL
MeSH Heading
Animal; Citrate (si)-Synthase|ME; Fumarate Hydratase|ME; Kidney Cortex|EN/UL; Malate Dehydrogenase|ME; Male; Mitochondria|EN; Oxidation-Reduction; Rats; Rats, Inbred Strains; Sulfurtransferases|ME; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.; 3-Hydroxyacyl CoA Dehydrogenases|ME

Publication Type
JOURNAL ARTICLE
ISSN
0022-1554
Country of Publication
UNITED STATES


Record 47 from database: MEDLINE
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Title
Mode of action of the yeast Saccharomyces cerevisiae as a feed additive for ruminants.
Author
Newbold CJ; Wallace RJ; McIntosh FM
Address
Rowett Research Institute, Bucksburn, Aberdeen.
Source
Br J Nutr, 1996 Aug, 76:2, 249-61
Abstract
Two suggested modes of action of yeast in stimulating rumen fermentation were investigated. The first, that yeast respiratory activity protects anaerobic rumen bacteria from damage by O2, was tested using different strains of yeast that had previously been shown to have differing abilities to increase the viable count of rumen bacteria. Saccharomyces cerevisiae NCYC 240, NCYC 1026, and the commercial product Yea-Sacc, added to rumen fluid in vitro at 1.3 mg/ml, increased the rate of O2 disappearance by between 46 and 89%. The same three preparations also stimulated bacterial numbers in an in vitro fermenter (Rusitec). S. cerevisiae NCYC 694 and NCYC 1088, which had no influence on the viable count in Rusitec, also had no effect on O2 uptake. Respiration-deficient (RD) mutants of S. cerevisiae NCYC 240 and NCYC 1026 were enriched by repeated culturing in the presence of ethidium bromide. S. cerevisiae NCYC 240 and NCYC 1026 stimulated the total and cellulolytic bacterial populations in Rusitec, while the corresponding RD mutants did not. Rigorous precautions to exclude air from Rusitec resulted in S. cerevisiae NCYC 240 no longer stimulating total bacterial numbers, although it still increased numbers of cellulolytic bacteria. The second hypothesis, that yeast provides malic and other dicarboxylic acids which stimulate the growth of some rumen bacteria, was examined by comparing the effects of yeast and malic acid on rumen fermentation in sheep. Three mature sheep were given 0.85 kg barley/d plus 0.55 kg chopped ryegrass hay/d either unsupplemented, or supplemented with 4 g S. cerevisiae NCYC 240/d or 100 mg L-malic acid/d either mixed with the diet or in aqueous solution infused continuously into the rumen. Yeast increased the total viable count of bacteria (P < 0.05) whereas malic acid did not, and no other effect of the treatments reached statistical significance. It was concluded, therefore, that the stimulation of rumen bacteria by S. cerevisiae is at least partly dependent on its respiratory activity, and is not mediated by malic acid.
Language of Publication
English
Unique Identifier
96408914

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MeSH Heading (Major)
Bacteria|*ME; Fermentation|*/DE; Food Additives|*; Rumen|*ME/MI; Saccharomyces cerevisiae|*; Sheep|*ME
MeSH Heading
Animal; Malates|PD; Oxygen|ME; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0007-1145
Country of Publication
ENGLAND


Record 48 from database: MEDLINE
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Title
Cloning and analysis of the C4 photosynthetic NAD-dependent malic enzyme of amaranth mitochondria.
Author
Long JJ; Wang JL; Berry JO
Address
Department of Biological Sciences, State University of New York at Buffalo 14260.
Source
J Biol Chem, 1994 Jan, 269:4, 2827-33
Abstract
In some C4 plant species, a mitochondrial NAD-dependent malic enzyme (EC 1.1.1.39) (NAD-ME) catalyzes the decarboxylation of 4 carbon malate in the bundle sheath cells, releasing CO2 for the Calvin cycle of photosynthesis. In amaranth, a dicotyledonous NAD-ME-type C4 plant, the photosynthetic NAD-ME purified as two subunits of 65 and 60 kDa, designated alpha and beta, respectively. Antiserum raised against the alpha subunit reacted only with the 65-kDa protein in immunoblot analysis. Immunogold electron microscopy using the alpha subunit antiserum demonstrated that this protein was localized specifically to the mitochondrial matrix of bundle sheath cells. The complete nucleotide sequence of a 2300-base pair alpha subunit cDNA clone showed that this gene encodes a protein that contains all of the motifs required for a complete and functional malic enzyme. The alpha subunit has significant similarity along its entire length to other known NAD- and NADP-dependent malic enzymes from plants, animals, and bacteria. The findings presented here provide new insights about the C4 photosynthetic NAD-ME and its evolutionary relationship to other forms of malic enzyme present in eukaryotic and prokaryotic organisms.
Language of Publication
English
Unique Identifier
94132054

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MeSH Heading (Major)
Malate Dehydrogenase|AN/*BI/IP; Photosynthesis|*; Plants|*EN
MeSH Heading
Amino Acid Sequence; Animal; Bacillus stearothermophilus|EN; Base Sequence; Blotting, Western; Chloroplasts|EN; Cloning, Molecular; Comparative Study; Conserved Sequence; Corn|EN; Human; Macromolecular Systems; Mice; Microscopy, Immunoelectron; Mitochondria|EN; Molecular Sequence Data; Sequence Homology, Amino Acid; Support, U.S. Gov't, Non-P.H.S.

Publication Type
JOURNAL ARTICLE
ISSN
0021-9258
Country of Publication
UNITED STATES


Record 49 from database: MEDLINE
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Title
[U-13C]glutamate metabolism in rat brain mitochondria reveals malic enzyme activity.
Author
Bakken IJ; Sonnewald U; Clark JB; Bates TE
Address
Institute of Physics, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
Source
Neuroreport, 1997 May, 8:7, 1567-70
Abstract
13C nuclear magnetic resonance spectroscopy was used to study the activity of malic enzyme in isolated brain mitochondria from rat in the presence of unlabelled malate and [U-13C]glutamate. ADP, inorganic phosphate, malate and [U-13C]glutamate were added to a suspension of oxygenated mitochondria. Typical tricarboxylic acid (TCA) cycle constituents (malate, 2-oxoglutarate and succinate) were labelled from [U-13C]glutamate and detected in the superfusion medium. The labelling patterns in the different atom positions of glutamate revealed entry of both unlabelled and labelled acetyl-CoA into the TCA cycle. Unlabelled acetyl-CoA was derived via pyruvate from exogenously applied malate by the action of mitochondrial malic enzyme, while labelled acetyl-CoA was derived from TCA cycle intermediates, most likely by the action of mitochondrial malic enzyme on malate produced from [U-13C]glutamate. The results demonstrate malic enzyme activity and pyruvate recycling in isolated rat brain mitochondria.
Language of Publication
English
Unique Identifier
97333766

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MeSH Heading (Major)
Brain|EN/*ME; Glutamic Acid|*ME; Malate Dehydrogenase|*ME; Malates|*ME; Mitochondria|EN/*ME
MeSH Heading
Animal; Carbon Isotopes; In Vitro; Male; Nuclear Magnetic Resonance; Pyruvates|ME; Rats; Rats, Wistar; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0959-4965
Country of Publication
ENGLAND


Record 50 from database: MEDLINE
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Title
The NADPH consumption regulates the NADPH-producing pathways (pentose phosphate cycle and malic enzyme) in rat adipocytes.
Author
Fabregat I; Revilla E; Machado A
Address
Source
Mol Cell Biochem, 1987 Mar, 74:1, 77-81
Abstract
The changes in the activity of the pentose phosphate cycle and the malic enzyme produced by the activation or inhibition of different NADPH-consuming pathways have been studied. The inhibition of the fatty acid synthesis by kynurenate produced a decrease in the flux through the pentose phosphate cycle and a diminution in the malic enzyme pathway. The incubation of the adipocytes in the presence of ter-butyl-hydroperoxide, a compound which is metabolized via a NADPH-consuming pathway, produced a big increase in the pentose phosphate cycle and the malic enzyme activities. The regulation of these NADPH-producing pathways by the NADPH/NADP ratio is discussed.
Language of Publication
English
Unique Identifier
87228747

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MeSH Heading (Major)
Adipose Tissue|*ME; Malate Dehydrogenase|*ME; NADP|*ME; Pentosephosphate Pathway|*/DE
MeSH Heading
Animal; Carmustine|PD; Female; Kinetics; Kynurenic Acid|PD; Oxidation-Reduction; Peroxides|PD; Rats; Rats, Inbred Strains; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0300-8177
Country of Publication
NETHERLANDS


Record 51 from database: MEDLINE
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Title
Effects of growth hormone on lipogenic enzyme activities in cultured rat hepatocytes.
Author
Schaffer WT
Address
Source
Am J Physiol, 1985 Jun, 248:6 Pt 1, E719-25
Abstract
The presence of cloned methionyl human growth hormone at 1 microgram/ml medium for the final 5 days of a 6-day culture period decreased the activity of malic enzyme (EC 1.1.1.40) 45% from 202 to 112, fatty acid synthetase 52% from 26 to 12, and ATP citrate lyase (EC 4.1.3.8) 20% from 192 to 154 nmol NADPH.min-1.mg-1 supernatant protein in rat hepatocytes maintained in serum-free primary culture. Also, the activity of mitochondrial glycerol-3-phosphate dehydrogenase (EC 1.1.99.5) decreased 52% from 20 to 9 nmol.min-1.mg-1 mitochondrial protein. In the same cells, no changes were observed in the activity of 6-phosphogluconate dehydrogenase (EC 1.1.1.44) and lactate dehydrogenase (EC 1.1.1.27). Glucose-6-phosphate dehydrogenase (EC 1.1.1.49) was increased 2.4-fold from 70 to 183 nmol.min-1.mg-1 protein, indicating the activity of this enzyme was paradoxically increased, whereas other enzymes involved in lipogenesis were decreased. Half-maximal decrease of malic enzyme activity and increase of glucose-6-phosphate dehydrogenase activity occurred at 10 and 3 ng methionyl human growth hormone per milliliter medium, respectively. These values are within the range of normal circulating growth hormone concentrations in the rat. The effects on malic enzyme and glucose-6-phosphate dehydrogenase appeared after 3-day exposure to growth hormone. These findings are consistent with the hypothesis that growth hormone antagonizes the action of agents that stimulate the activity of malic enzyme while concomitantly increasing the extractable activity of glucose-6-phosphate dehydrogenase.
Language of Publication
English
Unique Identifier
85222657

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MeSH Heading (Major)
Hormones, Synthetic|*PD; Liver|CY/DE/*EN; Somatotropin|*AA/PD
MeSH Heading
Animal; ATP Citrate (pro-S)-Lyase|ME; Cells, Cultured; Fatty Acid Synthetase Complex|ME; Glucosephosphate Dehydrogenase|ME; Lactate Dehydrogenase|ME; Malate Dehydrogenase|ME; Male; Phosphogluconate Dehydrogenase|ME; Rats; Rats, Inbred Strains; Time Factors

Publication Type
JOURNAL ARTICLE
ISSN
0002-9513
Country of Publication
UNITED STATES


Record 52 from database: MEDLINE
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Title
Nutritional regulation of lipogenic enzyme gene expression in rat epididymal adipose tissue.
Author
Iritani N; Fukuda H; Tada K
Address
Tezukayama Gakuin College, Osaka.
Source
J Biochem (Tokyo), 1996 Aug, 120:2, 242-8
Abstract
The time courses of gene expression, and the nutritional regulation of gene expression of lipogenic enzymes (acetyl-CoA carboxylase, fatty acid synthase, ATP citrate-lyase, malic enzyme, and glucose-6-phosphate dehydrogenase) in epididymal adipose tissue after refeeding food-deprived rats have been investigated and compared with those in liver (previously reported). The mRNA concentrations of lipogenic enzymes reached maximum levels at 24 h after the refeeding in adipose tissue and at 8-16 h in liver, while the enzyme induction reached maximum at 48-72 h in both tissues. Moreover, the mRNAs were more strongly induced in adipose tissue than in liver, whereas the enzyme induction (except malic enzyme) was lower. In adipose tissue of rats fed a carbohydrate diet without protein, the mRNA concentrations of acetyl-CoA carboxylase, ATP-citrate lyase, malic enzyme, and fatty acid synthase reached comparable levels to those of the carbohydrate/protein diet group. The protein feeding increased the enzyme induction in adipose tissue. As regards reduction of gene expression, lipogenic enzyme mRNA concentrations were not so markedly reduced by starvation or polyunsaturated fatty acids in adipose tissue as in liver. The differences in regulation of lipogenic enzyme gene expression and induction between adipose tissue and liver can be ascribed to tissue specificity.
Language of Publication
English
Unique Identifier
97044735

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MeSH Heading (Major)
Adipose Tissue|DE/EN/*ME; Lipids|*BI
MeSH Heading
Acetyl-CoA Carboxylase|BI/GE; Animal; Animal Nutrition; ATP Citrate (pro-S)-Lyase|BI/GE; Diabetes Mellitus, Experimental|EN/GE/ME; Enzyme Induction; Epididymis|DE/EN/ME; Fatty Acid Synthetase Complex|BI/GE; Food Deprivation; Gene Expression Regulation, Enzymologic|DE; Glucosephosphate Dehydrogenase|BI/GE; Insulin|PD; Liver|DE/EN/ME; Malate Dehydrogenase|BI/GE; Male; Organ Specificity; Rats; Rats, Wistar; RNA, Messenger|GE/ME; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0021-924X
Country of Publication
JAPAN


Record 53 from database: MEDLINE
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Title
Membrane enzymes associated with the dissimilation of some citric acid cycle substrates and production of extracellular oxidation products in chemostat cultures of Pseudomonas fluorescens.
Author
Lee WS; Cooper JK; Lynch WH
Address
Source
Can J Microbiol, 1984 Mar, 30:3, 396-405
Abstract
Enzyme activities forming extracellular products from succinate, fumarate, and malate were examined using washed cell suspensions of Pseudomonas fluorescens from chemostat cultures. Membrane-associated enzyme activities (glucose, gluconate, and malate dehydrogenases), producing large accumulations of extracellular oxidation products in carbon-excess environments, have previously been found in P. fluorescens. Investigations carried out here have demonstrated the presence in this microorganism of a malic enzyme activity which produces extracellular pyruvate from malate in carbon-excess environments. Although the three membrane dehydrogenase enzymes decrease significantly in carbon-limited chemostat cultures, malic enzyme activity was found to increase fourfold under these conditions. The regulation of malate dehydrogenase and malic enzyme by malate or succinate was similar. Malate dehydrogenase increased and malic enzyme decreased in carbon-excess cultures. The opposite effect was observed in carbon-limited cultures. When pyruvate or glucose was used as the carbon source, malate dehydrogenase was regulated similarly by the available carbon concentration, but malic enzyme activity producing extracellular pyruvate was not detected. While large accumulations of extracellular oxalacetate and pyruvate were produced in malate-excess cultures, no extracellular oxidation products were detected in succinate-excess cultures. This may be explained by the lack of detectable activity for the conversion of added external succinate to extracellular fumarate and malate in cells from carbon-excess cultures. In cells from carbon-limited (malate or succinate) cultures, very active enzymes for the conversion of succinate to extracellular fumarate and malate were detected. Washed cell suspensions from these carbon-limited cultures rapidly oxidized added succinate to extracellular pyruvate through the sequential action of succinate dehydrogenase, fumarase, and malic enzyme. Succinate dehydrogenase and fumarase activities producing extracellular products were not detected in cells from chemostat cultures using pyruvate or glucose as the carbon source. Uptake activities for succinate, malate, and pyruvate also were found to increase in carbon-limited (malate or succinate) and decrease in carbon-excess cultures. The role of the membrane-associated enzymes forming different pathways for carbon dissimilation in both carbon-limited and carbon-excess environments is discussed.
Language of Publication
English
Unique Identifier
84205142

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MeSH Heading (Major)
Citric Acid Cycle|*; Pseudomonas fluorescens|*EN
MeSH Heading
Ammonia|ME; Carbohydrate Dehydrogenases|ME; Cell Membrane|EN; Fumarate Hydratase|ME; Fumarates|ME; Glucose|ME; Glucose Dehydrogenases|ME; Malate Dehydrogenase|ME; Malates|ME; Oxaloacetates|ME; Oxidation-Reduction; Pseudomonas|ME; Pyruvates|BI; Succinate Dehydrogenase|ME; Succinates|ME; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0008-4166
Country of Publication
CANADA


Record 54 from database: MEDLINE
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Title
Comparative study of lipogenic enzymes in several vertebrates.
Author
Iritani N; Ikeda Y; Fukuda H; Katsurada A
Address
Source
Lipids, 1984 Nov, 19:11, 828-35
Abstract
The liver lipogenic enzymes are compared among rats, chickens, frogs and fish. Although the apparent Km values of glucose-6-phosphate dehydrogenase for glucose-6-phosphate are not much different among all the species, those of malic enzyme for malate are much higher in chickens and fish than in rats and frogs. Glucose-6-phosphate dehydrogenase showed very high activities compared with malic enzyme in fish liver, and malic enzyme showed high activities in chicken liver. Although the apparent Km values of acetyl-CoA carboxylase and fatty acid synthetase for substrates are in the same range among all the animals, the activity of acetyl-CoA carboxylase seems to be extremely low in fish and frog livers, and that of fatty acid synthetase is low in frog livers only. In addition, the apparent Km values of alpha-glycerophosphate acyltransferase of fish liver are very high, and the enzyme activity appears to be extremely low compared to the others. Therefore, the enzymes at the first steps of both fatty acid and glycerolipid syntheses of poikilothermos animals appear to be very low. On the other hand, the Ouchterlony double-diffusion patterns showed that the lipogenic enzymes of chickens, frogs and fish are immunologically different from those of rats, with the exception of acetyl-CoA carboxylase in chickens. Therefore, it is suggested that the fatty acid and glycerolipid forming systems of poikilothermos animals are quite different from those of homoiothermos and the lipogenesis is very low in poikilothermos.
Language of Publication
English
Unique Identifier
85110305

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MeSH Heading (Major)
Lipids|*BI
MeSH Heading
Acetic Acids|ME; Acetyl-CoA Carboxylase|ME; Acyltransferases|ME; Animal; Bufonidae; Chickens; Comparative Study; Diet; Fatty Acid Synthetase Complex|ME; Fishes; Glucosephosphate Dehydrogenase|ME; Glycerol-3-Phosphate O-Acyltransferase|ME; Immunodiffusion; Kinetics; Liver|EN; Malate Dehydrogenase|ME; Male; Rats; Rats, Inbred Strains

Publication Type
JOURNAL ARTICLE
ISSN
0024-4201
Country of Publication
UNITED STATES


Record 55 from database: MEDLINE
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Title
Hexanoate and octanoate inhibit transcription of the malic enzyme and fatty acid synthase genes in chick embryo hepatocytes in culture.
Author
Roncero C; Goodridge AG
Address
Department of Biochemistry, University of Iowa, Iowa City 52242.
Source
J Biol Chem, 1992 Jul, 267:21, 14918-27
Abstract
Hexanoate and octanoate inhibit the triiodothyronine (T3)-induced increases in the activities of malic enzyme and fatty acid synthase in chick embryo hepatocytes in culture. Butanoate was less effective as an inhibitor, and palmitate, stearate, and oleate had no effect or small stimulatory effects. Hexanoate and octanoate inhibited the lipogenic enzyme activities at a transcriptional step, and did so within 30 min of addition. Incubation for 2 h in the absence of fatty acid reversed the inhibition of transcription caused by hexanoate. The inhibitory effect of hexanoate was selective because DNA content and transcription of the glyceraldehyde-3-phosphate dehydrogenase and beta-actin genes were not inhibited. Hexanoate-mediated inhibition of transcription rates of the lipogenic genes was not correlated with an inhibition of binding of T3 to its nuclear receptor. 2-Bromooctanoate and carnitine stimulated the T3-induced accumulation of the mRNAs for malic enzyme and fatty acid synthase. The presence of hexanoate stimulated by 2- to 3-fold the increase caused by carnitine, suggesting that hexanoate and carnitine may regulate lipogenic gene expression by a common pathway. Hexanedioate, acetoacetate, beta-hydroxybutyrate, branched chain fatty acids, and branched chain keto acids had little or no effect on abundance of the lipogenic mRNAs. We suggest that the active inhibitor is a metabolite derived from hexanoate or octanoate, possibly an intermediate derived from an acyl-CoA derivative.
Language of Publication
English
Unique Identifier
92340537

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MeSH Heading (Major)
Fatty Acid Synthetase Complex|*GE; Hexanoic Acids|*PD; Liver|CY/EM/*EN; Malate Dehydrogenase|*GE; Octanoic Acids|*PD; Transcription, Genetic|*DE
MeSH Heading
Actins|GE; Animal; Blotting, Northern; Carnitine|PD; Cells, Cultured; Chick Embryo; Drug Interactions; Glucagon|PD; Glyceraldehyde-3-Phosphate Dehydrogenases|GE; RNA, Messenger|ME; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.; Triiodothyronine|PD

Publication Type
JOURNAL ARTICLE
ISSN
0021-9258
Country of Publication
UNITED STATES


Record 56 from database: MEDLINE
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Title
Cloning and molecular characterization of two genes encoding adhesion proteins involved in Trichomonas vaginalis cytoadherence.
Author
Alderete JF; OBrien JL; Arroyo R; Engbring JA; Musatovova O; Lopez O; Lauriano C; Nguyen J
Address
Department of Microbiology, University of Texas Health Science Center, San Antonio 78284-7758, USA.
Source
Mol Microbiol, 1995 Jul, 17:1, 69-83
Abstract
Cytoadherence to the vaginal epithelium is a critical step in infection by the eukaryotic flagellate Trichomonas vaginalis. Four trichomonad surface proteins (AP65, AP51, AP33 and AP23) mediate cytoadherence. The cDNA encoding the AP65 adhesin was isolated from a phagemid cDNA expression library by screening with antiserum and monoclonal antibody (mAb) raised against the purified trichomonad AP65 protein. Two clones, F11.2 and F11.5, coded for immuno-crossreactive recombinant proteins that possessed functional properties equal to the T. vaginalis AP65 adhesin. Analysis of full-length sequences corresponding to the F11.2 and F11.5 cDNAs revealed that both contained 1701-base open reading frames (ORFs) that encoded proteins of 63 281 daltons and 83 087 daltons, respectively. Comparison of the full-length sequences showed 87% identity at the nucleotide level and 91% identity at the protein level. Restriction-enzyme mapping and Southern analysis reaffirmed the distinctness of the F11.2 and F11.5 cDNAs, indicating that two different AP65 genes (now called ap65-1 and ap65-2) are present in the T. vaginalis genome in at least two copies each. Northern analysis detected high levels of transcript of approximately 1.8 kb for both ap65-1 and ap65-2 genes in trichomonads grown only in high-iron medium, confirming the transcriptional regulation of adhesin synthesis by iron. Homology searches revealed significant similarity (38% amino acid identity and 54% nucleotide identity) to malic enzymes. However, purified malic enzyme and mAb to AP65 crossreactive with malic enzyme neither inhibited cytoadherence of T. vaginalis to host cells nor prevented binding of the trichomonad AP65 to HeLa cells in a ligand assay.
Language of Publication
English
Unique Identifier
96020663

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MeSH Heading (Major)
Genes, Structural, Protozoan|*GE; Iron|*PD; Protozoan Proteins|CH/*GE/ME; Trichomonas vaginalis|*GE
MeSH Heading
Amino Acid Sequence; Animal; Base Sequence; Cell Adhesion|GE; Cloning, Molecular; DNA, Complementary|GE; Hela Cells|ME; Human; Molecular Sequence Data; Multigene Family|GE; Promoter Regions (Genetics)|GE; Recombinant Fusion Proteins|BI/ME; Restriction Mapping; RNA, Messenger|BI; RNA, Protozoan|BI; Sequence Homology, Amino Acid; Sequence Homology, Nucleic Acid; Support, U.S. Gov't, P.H.S.; Transcription, Genetic|DE

Publication Type
JOURNAL ARTICLE
ISSN
0950-382X
Country of Publication
ENGLAND


Record 57 from database: MEDLINE
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Title
Characterization of the vacuolar ATPase activity of the crassulacean-acid-metabolism plant Kalanchoë daigremontiana. Receptor modulating.
Author
Smith JA; Uribe EG; Ball E; Heuer S; Lüttge U
Address
Source
Eur J Biochem, 1984 Jun, 141:2, 415-20
Abstract
Plants performing crassulacean acid metabolism show a large nocturnal accumulation of malic acid in the vacuole of the photosynthetic cells. It has been postulated that an H+-translocating ATPase energizes the transport of malic acid across the tonoplast into the vacuole. In the present work we have characterized the ATPase activity associated with vacuoles of the crassulacean-acid-metabolism plant Kalanchoë daigremontiana and compare it with other phosphohydrolases. Vacuoles were isolated by polybase-induced lysis of mesophyll-cell protoplasts. The vacuoles had a high activity of unspecific acid phosphatase (pH optimum 5.3). The acid phosphatase was strongly inhibited by ammonium molybdate (with 50% inhibition at about 0.5 mmol m-3), but was not completely inhibited even at much higher ammonium-molybdate concentrations. In contrast, the vacuolar ATPase activity, assayed in the presence of 100 mmol m-3 ammonium molybdate, had a pH optimum of 8.0. ATP was the preferred substrate, but GTP, ITP and ADP were hydrolyzed at appreciable rates. The mean ATPase activity at pH 8.0 was 14.5 nmol h-1 (10(3) vacuoles)-1, an average 13% of which was attributable to residual acid-phosphatase activity. Inorganic-pyrophosphatase activity could not be demonstrated unambiguously. The vacuolar ATPase activity was Mg2+-dependent, had an apparent Km for MgATP2- of 0.31 mol m-3, and was 32% stimulated by 50 mol m-3 KCl. Of the inhibitors tested, oligomycin slightly inhibited the vacuolar ATPase activity and diethylstilbestrol and NO-3 were both markedly inhibitory. Dicyclohexylcarbodiimide and tributyltin were also strongly inhibitory. Tributyltin caused a 50% inhibition at about 0.3 mmol m-3. This is taken as evidence that the vacuolar ATPase might function as an H+-translocating ATPase. It is shown that the measured activity of the vacuolar ATPase would be of the right order to account for the observed rates of nocturnal malic-acid accumulation in K. daigremontiana.
Language of Publication
English
Unique Identifier
84236176

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MeSH Heading (Major)
Adenosinetriphosphatase|AI/*ME; Chloroplasts|*EN; Organoids|*EN; Photosynthesis|*; Plants|*EN/UL; Vacuoles|*EN
MeSH Heading
Acid Phosphatase|ME; Catalysis; Hydrogen-Ion Concentration; Hydrolysis; Malates|ME; Substrate Specificity; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0014-2956
Country of Publication
GERMANY, WEST


Record 58 from database: MEDLINE
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Title
Kinetics of induction by thyroid hormone of the two hepatic mRNAs coding for cytosolic malic enzyme in the hypothyroid and euthyroid states. Evidence against an obligatory role of S14 protein in malic enzyme gene expression.
Author
Strait KA; Kinlaw WB; Mariash CN; Oppenheimer JH
Address
Department of Medicine, University of Minnesota, Minneapolis 55455.
Source
J Biol Chem, 1989 Nov, 264:33, 19784-9
Abstract
In rat liver, triiodothyronine (T3) and dietary carbohydrate induce the expression of the genes coding for malic enzyme (ME) (EC 1.1.1.40) and S14 protein. The mRNAs for both ME and S14 are elevated under circumstances associated with augmented lipogenesis. Since the lag time in the induction of mRNA coding for S14 is short (20 min) and the lag time in the induction of the mRNA for ME is relatively long (2-6 h), the possibility arose that the induction of the ME gene by T3 was mediated by S14 protein. To test this hypothesis we examined the temporal relationship between the accumulation of the hepatic S14 protein and the mRNAs coding for ME. In confirmation of previous reports, we found that two mRNAs coded for ME, one 27 S and the other 21 S in size. The level of enzyme activity generated appeared to be determined by both mRNA species. Sequencing of the 27 S fragment established that this mRNA is generated as a consequence of the use of an alternate polyadenylation site downstream to that used in the 21 S mRNA. Unanticipated from the earlier descriptions was the finding of a markedly asynchronous response of these mRNAs to T3 in hypothyroid animals. The lag time following T3 administration was 90 min for the 27 S and fully 8-12 h for the smaller 21 S sequence. Despite the rapid rise of mRNA S14, the S14 protein could not be detected for approximately 12 h after T3 administration. This ruled out the possibility that S14 is an obligate mediator in the induction of the ME gene. A contrasting pattern was observed in the euthyroid state where both ME mRNAs had indistinguishable lag times of 2-3 h, and the S14 protein rose within the same time frame. The delayed response of the 21 S mRNA for malic enzyme in hypothyroid animals thus appears to be due to a reversible defect in the transcription of the ME gene.
Language of Publication
English
Unique Identifier
90062081

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MeSH Heading (Major)
Gene Expression Regulation, Enzymologic|*/DE; Genes, Structural|*/DE; Hypothyroidism|*EN; Liver|DE/*EN; Malate Dehydrogenase|BI/*GE; RNA, Messenger|BI/DE/*GE; Thyroid Gland|*PH; Transcription, Genetic|*/DE; Triiodothyronine|*PD
MeSH Heading
Animal; Base Sequence; Comparative Study; Kinetics; Male; Molecular Sequence Data; Nucleic Acid Hybridization; Rats; Rats, Inbred Strains; Reference Values; Restriction Mapping; Sequence Homology, Nucleic Acid; Support, U.S. Gov't, P.H.S.

Publication Type
JOURNAL ARTICLE
ISSN
0021-9258
Country of Publication
UNITED STATES


Record 59 from database: MEDLINE
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Title
Structural characterization of the rat malic enzyme gene.
Author
Morioka H; Magnuson MA; Mitsuhashi T; Song MK; Rall JE; Nikodem VM
Address
Clinical Endocrinology Branch, National Institute of Diabetes, Digestive, and Kidney Diseases, Bethesda, MD 20892.
Source
Proc Natl Acad Sci U S A, 1989 Jul, 86:13, 4912-6
Abstract
We have identified and characterized lambda bacteriophage clones containing genomic DNA encoding rat malic enzyme [(S)-malate:NADP+ oxidoreductase (oxaloacetate-decarboxylating); EC 1.1.1.40]. The malic enzyme gene is unexpectedly large, spanning at least 95 kilobases. It is divided into 14 exons that range in size from 76 to 1513 base pairs. The sizes and boundaries of the exons were determined by Southern blotting and DNA sequencing. The sequences at the 5' and 3' ends of each intron conformed to the consensus sequence for mammalian introns. S1 nuclease and primer-extension assays showed that transcription of the malic enzyme gene initiates at multiple sites, the strongest one at position -31 relative to the ATG. "TATA and CCAAT box" homologies are not present in the proximal promoter region. Analysis of the 3' end of the gene showed that the utilization of alternate polyadenylylation signals in exon 14 results in two mRNAs with 3' untranslated regions of 345 and 1345 nucleotides, respectively.
Language of Publication
English
Unique Identifier
89296914

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MeSH Heading (Major)
Genes, Structural|*; Malate Dehydrogenase|*GE
MeSH Heading
Amino Acid Sequence; Animal; Base Sequence; Cloning, Molecular; Exons; Introns; Molecular Sequence Data; Nucleic Acid Conformation; Rats; Restriction Mapping; RNA, Messenger|GE

Publication Type
JOURNAL ARTICLE
ISSN
0027-8424
Country of Publication
UNITED STATES


Record 60 from database: MEDLINE
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Title
Primary structure of the hydrogenosomal malic enzyme of Trichomonas vaginalis and its relationship to homologous enzymes.
Author
Hrdý I; Müller M
Address
Rockefeller University, New York, New York 10021, USA.
Source
J Eukaryot Microbiol, 1995 Sep, 42:5, 593-603
Abstract
The complete nucleotide sequence has been established for two genes (maeA and maeB) coding for different subunits of the hydrogenosomal malic enzyme [malate dehydrogenase (decarboxylating) EC 1.1.1.39] of Trichomonas vaginalis. Two further genes (maeC and maeD) of this enzyme have been partially sequenced. The complete open reading frames code for polypeptides of 567 amino acids in length. These two open reading frames are similar with less than 12 percent pairwise nucleotide differences and less than 9 percent pairwise amino acid differences. The open reading frames of the two partially sequenced genes correspond to the amino-terminal part of the polypeptides coded and are similar to the corresponding parts of the completely sequenced ones. The deduced translation products of the two complete genes differ in their calculated pI values by 1.5 pH unit. The genes code for polypeptides which contain 12 or 11 amino-terminal amino-acyl residues not present in the proteins isolated from the cell. Other hydrogenosomal enzymes also have similar amino-terminal extensions which probably play a role in organellar targeting and translocation of the newly synthesized polypeptides. A comparison of 19 related enzymes from bacteria and eukaryotes with the maeA product revealed 34-45 percent amino acid identity. Phylogenetic reconstruction based on nonconservative amino acid differences with maximum parsimony (phylogenetic analysis using parsimony, PAUP) and distance based (neighbor-joining, NJ) methods showed that the T. vaginalis enzyme is the most divergent of all eukaryotic malic enzymes, indicating its long independent evolutionary history.
Language of Publication
English
Unique Identifier
96010590

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MeSH Heading (Major)
Malate Dehydrogenase|*GE; Phylogeny|*; Sequence Homology, Amino Acid|*; Trichomonas vaginalis|*EN/GE
MeSH Heading
Amino Acid Sequence; Animal; Cloning, Molecular; Genes, Structural, Protozoan|GE; Molecular Sequence Data; Sequence Alignment; Sequence Analysis; Sequence Analysis, DNA; Sequence Homology, Nucleic Acid; Support, U.S. Gov't, P.H.S.

Publication Type
JOURNAL ARTICLE
ISSN
1066-5234
Country of Publication
UNITED STATES


Record 61 from database: MEDLINE
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Title
Survival of Escherichia coli O157:H7 in synthetic gastric fluid after cold and acid habituation in apple juice or trypticase soy broth acidified with hydrochloric acid or organic acids.
Author
Uljas HE; Ingham SC
Address
Department of Food Science, University of Wisconsin-Madison 53706, USA.
Source
J Food Prot, 1998 Aug, 61:8, 939-47
Abstract
Extreme acid tolerance of Escherichia coli O157:H7 has raised doubts about the safety of acidic foods. This study examined whether prior storage in acidic and/or cold conditions enhanced survival of E. coli O157:H7 in synthetic gastric fluid (SGF). Three E. coli O157:H7 strains were stored in trypticase soy broth (TSB; acidified with HCl, malic acid, citric acid, or lactic acid) or pH 3.5 and 6.5 (nonacidic control) apple juice at 4 and 21 degrees C for < or = 7 days and then were incubated in pH 2.5 SGF at 37 degrees C for 4 h. Cells survived better in apple juice than in TSB containing organic acids, suggesting that juice constituents other than organic acids protect E. coli O157:H7. Refrigeration combined with low pH best protected cells in apple juice and acidified TSB, but, compared to the nonacidic control, only acidified TSB enhanced subsequent survival in pH 2.5 SGF. Equal survival in SGF occurred after storage in pH 3.5 or 6.5 apple juice at 4 degrees C, suggesting that low temperature alone in apple juice enhanced acid tolerance. Two strains stored at 4 degrees C in TSB containing malic or citric acid subsequently survived better in SGF than cells stored in nonacidified TSB but poorer than cells stored in the presence of HCl. These differences reflect the higher pKa of these organic acids. However, subsequent survival of these strains in SGF was poorer after refrigerated storage in apple juice than in TSB containing citric or malic acids. Cells stored in lactic acid were most likely to be completely eliminated upon transfer to SGF. Differences in survival in storage media or SGF related to strain, storage conditions, or acidifier were consistent and often statistically significant (P < 0.05). Although the survival of E. coli O157:H7 in refrigerated acidic beverages may not be affected by the type of acidifier used, the subsequent survival in SGF of this pathogen may be critically dependent on this factor.
Language of Publication
English
Unique Identifier
98379373

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MeSH Heading (Major)
Beverages|*MI; Caseins|*PD; Escherichia coli|*PH; Protein Hydrolysates|*PD
MeSH Heading
Cold; Hydrochloric Acid|PD; Hydrogen-Ion Concentration; Rosales; Support, Non-U.S. Gov't; Support, U.S. Gov't, Non-P.H.S.; Temperature

Publication Type
JOURNAL ARTICLE
ISSN
0362-028X
Country of Publication
UNITED STATES


Record 62 from database: MEDLINE
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Title
The peroxisome proliferator activated receptor regulates malic enzyme gene expression.
Author
Castelein H; Gulick T; Declercq PE; Mannaerts GP; Moore DD; Baes MI
Address
Laboratory of Clinical Chemistry, Faculty of Pharmaceutical Sciences, Catholic University of Leuven, Belgium.
Source
J Biol Chem, 1994 Oct, 269:43, 26754-8
Abstract
A new regulatory element for peroxisome proliferator activated receptor (PPAR)/retinoid X receptor (RXR) heterodimers was found in the promoter of the malic enzyme gene. Similar to previously characterized peroxisome proliferator response elements (PPREs), it consists of a direct repeat of sequences related to the half-site consensus AGGTCA with an interspacing of 1 base pair. Specific binding of PPAR/RXR heterodimers to this element was demonstrated. Furthermore, this sequence conferred ciprofibrate responsiveness of a reporter through the homologous malic enzyme or heterologous thymidine kinase promoters. This PPRE presumably mediates the transcriptional effects of peroxisome proliferators on malic enzyme expression. The presence of a PPRE in the promoter of this lipogenic enzyme suggests a broader function for the PPAR in the regulation of lipid metabolism.
Language of Publication
English
Unique Identifier
95014534

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MeSH Heading (Major)
Gene Expression Regulation, Enzymologic|*; Malate Dehydrogenase|*GE; Promoter Regions (Genetics)|*GE; Receptors, Cytoplasmic and Nuclear|*ME; Transcription Factors|*ME
MeSH Heading
Animal; Antilipemic Agents|PD; Base Sequence; Clofibric Acid|AA/PD; DNA Mutational Analysis; Human; Mice; Molecular Sequence Data; Sequence Deletion; Support, Non-U.S. Gov't; Trans-Activation (Genetics)

Publication Type
JOURNAL ARTICLE
ISSN
0021-9258
Country of Publication
UNITED STATES


Record 63 from database: MEDLINE
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Title
Characterization of a bean (Phaseolus vulgaris L.) malic-enzyme gene.
Author
Walter MH; Grima Pettenati J; Feuillet C
Address
Institut fÂur Pflanzenphysiologie (260), UniversitÂat Hohenheim, Stuttgart, Germany.
Source
Eur J Biochem, 1994 Sep, 224:3, 999-1009
Abstract
We have isolated a genomic clone encoding a plant NADP(+)-dependent malic enzyme (NADP-ME). This clone, isolated from bean (Phaseolus vulgaris L.), covers the entire gene (exons, introns) and 5'-flanking regions. DNA sequencing defines 20 exons spanning approximately 4.5 kb, which range over 48-235 bp in size. All 19 introns are fairly small (79-391). The first intron resides in the 5'-untranslated leader sequence. Introns 10, 11 and 16 are located at positions identical to a rat malic-enzyme gene. In the promoter region, a TATA box (TATATATA) is easily recognized 41 bp upstream of a single transcription-initiation site. Two potential cis-acting elements with homology to elements from plant genes, activated by UV light and fungal elicitors, were identified at positions -153 and -312, respectively. Southern-blot analysis suggests a single gene copy, but also other distantly related genes, in the bean genome. The deduced NADP-ME protein of 589 amino acids exhibits features consistent with a cytoplasmic location. We describe the organization of the NADP-ME protein into functional domains located on separate exons. The evolution of malic-enzyme genes coding for isoforms in different cellular compartments of plants and animals is discussed.
Language of Publication
English
Unique Identifier
95010093

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MeSH Heading (Major)
Legumes|*EN; Malate Dehydrogenase|*GE; Plant Proteins|*GE
MeSH Heading
Amino Acid Sequence; Base Sequence; Cloning, Molecular; DNA, Plant; Exons; Genes, Plant; Introns; Molecular Sequence Data; Promoter Regions (Genetics); Sequence Homology, Amino Acid; Support, Non-U.S. Gov't; Transcription, Genetic

Publication Type
JOURNAL ARTICLE
ISSN
0014-2956
Country of Publication
GERMANY


Record 64 from database: MEDLINE
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Title
Isolation and characterization of Kluyveromyces marxianus mutants deficient in malate transport.
Author
Queiros O; Casal M; Althoff S; Moradas Ferreira P; Leao C
Address
Departamento de Biologia, Universidade do Minho, Braga, Portugal.
Source
Yeast, 1998 Mar, 14:5, 401-7
Abstract
In malic acid-grown cells of the strains ATCC 10022 and KMS3 of Kluyveromyces marxianus the transport of malic acid occurred by a malate-proton symport, which accepted L-malic, D-malic, succinic and fumaric acids, but not tartaric, malonic or maleic acids. The system was inducible and subjected to glucose repression. Mutants of the strain KMS3, unable to grow in a medium with malic acid, were isolated and checked for their capacity to utilize several carbon sources and to transport dicarboxylic acids by the malate-proton symport. Two distinct clones affected on malate transport were obtained. Both were able to grow on a medium with glycerol or ethanol but not with DL-malic, succinic, oxoglutaric and oxaloacetic acids as the sole carbon and energy sources. However, while one of the mutants (Mal7) displayed activity levels for the enzymes malate dehydrogenase, isocitrate lyase, and phosphoenolpyruvate carboxykinase similar to those of the wild strain, in the other mutant type (Mal6) the activities for the same enzymes were significantly reduced. Plasma membranes from derepressed cells of the wild strain and of the mutants Mal6 and Mal7 were isolated and the protein analysed by SDS-PAGE. The electrophoretic patterns of these preparations differed in a polypeptide with an apparent molecular mass of about 28 kDa, which was absent only in the mutant Mal7. The results indicated that Mal7 can be affected in a gene that encodes a malate carrier in K. marxianus.
Language of Publication
English
Unique Identifier
98220304

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MeSH Heading (Major)
Kluyveromyces|EN/GD/*GE/IP; Malates|*ME; Mutation|*
MeSH Heading
Biological Transport; Dicarboxylic Acids|ME; Electrophoresis, Polyacrylamide Gel; Genes, Fungal; Glucose|ME; Isocitrate Lyase|ME; Malate Dehydrogenase|ME; Membrane Proteins|AN; Protons; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0749-503X
Country of Publication
ENGLAND


Record 65 from database: MEDLINE
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Title
The effect of glycolic acid on cultured human skin fibroblasts: cell proliferative effect and increased collagen synthesis.
Author
Kim SJ; Won YH
Address
Department of Dermatology, Chonnam University Research Institute of Medical Science, Chonnam National University Medical School, Kwangju, Korea.
Source
J Dermatol, 1998 Feb, 25:2, 85-9
Abstract
Glycolic acid peeling is known to improve photoaging processes such as wrinkling and roughness, but this effect has not been clearly defined, even though functional activation of fibroblasts has been suggested. The study was aimed to determine the effects of glycolic acid and malic acid (AHA: alpha hydroxy acid) on cultured dermal fibroblasts. Whether it directly increases cell proliferation may be an important factor influencing the production of extracellular matrix such as type I collagen. Cultured human skin fibroblasts were treated for 24 hours with glycolic acid and malic acid at different concentrations (10(-4), 10(-5), 10(-6) M), and cell proliferation was measured by MTT assay. Then quantitative analysis of collagen synthesis was performed by PICP (Procollagen Type I C-peptide) enzyme immunoassay and radioisotope (3H-proline) labelled collagen assay. The results showed increased cell proliferation and collagen production in response to glycolic acid in a dose dependent manner. The range of cell proliferation and collagen production were significantly higher with glycolic acid treatment than with malic acid or control. It was suggested that the favorable effects of glycolic acid treatment on aging skin were mediated by increased cell proliferation in addition to functional activation of fibroblasts.
Language of Publication
English
Unique Identifier
98224378

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MeSH Heading (Major)
Cell Division|*DE; Collagen|BI/*DE; Fibroblasts|*DE/ME; Glycolates|*PD; Malates|*PD; Skin|CY/*DE/ME
MeSH Heading
Cells, Cultured; Comparative Study; Human; Immunoenzyme Techniques; Infant, Newborn; Male; Reference Values; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0385-2407
Country of Publication
JAPAN


Record 66 from database: MEDLINE
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Title
Cloning and sequence analysis of the gene encoding Lactococcus lactis malolactic enzyme: relationships with malic enzymes.
Author
Denayrolles M; Aigle M; Lonvaud Funel A
Address
Institut d'Oenologie, UniversitÆe de Bordeaux II, Talence, France.
Source
FEMS Microbiol Lett, 1994 Feb, 116:1, 79-86
Abstract
Malolactic enzyme is the key enzyme in the degradation of L-malic acid by lactic acid bacteria. Using degenerated primers designed from the first 20 N-terminal amino acid sequence of lactococcal malolactic enzyme, a 60-bp DNA fragment containing part of the mleS gene was amplified from Lactococcus lactis in a polymerase chain reaction. This specific probe was used to isolate two contiguous fragments covering the gene as a whole. The 1.9-kb region sequenced contains an open reading frame of 1623 bp, coding a putative protein of 540 amino acids. The deduced amino acid sequence reveals that lactococcal putative protein (Mlep) is highly homologous to the malic enzyme of other organisms. Expression of the mleS gene in Escherichia coli results in malolactic activity.
Language of Publication
English
Unique Identifier
94178715

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MeSH Heading (Major)
Lactococcus lactis|EN/*GE; Malate Dehydrogenase|*GE/ME
MeSH Heading
Amino Acid Sequence; Animal; Base Sequence; Cloning, Molecular; DNA, Bacterial; Escherichia coli; Human; Molecular Sequence Data; Open Reading Frames; Polymerase Chain Reaction; Restriction Mapping; Sequence Homology, Amino Acid

Publication Type
JOURNAL ARTICLE
ISSN
0378-1097
Country of Publication
NETHERLANDS


Record 67 from database: MEDLINE
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Title
A comparative study on the transport of L(-)malic acid and other short-chain carboxylic acids in the yeast Candida utilis: evidence for a general organic acid permease.
Author
Cássio F; Leão C
Address
Laboratory of Biology, University of Minho, Braga, Portugal.
Source
Yeast, 1993 Jul, 9:7, 743-52
Abstract
Cells of the yeast Candida utilis grown in medium with short-chain mono-, di- or tricarboxylic acids transported L(-)malic acid by two transport systems at pH 3.0. Results indicate that probably a proton symport for the ionized form of the acid and a facilitated diffusion for the undissociated form were present. Dicarboxylic acids such as succinic, fumaric, oxaloacetic and alpha-ketoglutaric acids were competitive inhibitors of the malic acid for the high-affinity system, suggesting that these acids used the same transport system. In turn, competitive inhibition uptake studies of labelled carboxylic acid in the low-affinity range indicated that this system was non-specific and able to accept not only carboxylic (mono-, di- or tri-) acids but also some amino acids. Additionally, under the same growth conditions, C. utilis produced two mediated transport systems for lactic acid: a proton symport for the anionic form which appeared to be a common monocarboxylate carrier and a facilitated diffusion system for the undissociated acid displaying a substrate specificity similar to that observed for the low-affinity dicarboxylic acid transport. The mediated carboxylic acid transport systems were inducible and subjected to repression by glucose. In glucose-grown cells the undissociated dicarboxylic acids entered the cells slowly by simple diffusion. Repressed glucose-grown cells were only able to produce both transport systems if an inducer, at low concentration (0.5%, w/v), was present during starvation in buffer. This process was inhibited by the presence of cycloheximide indicating that induction requires de novo protein synthesis. If a higher acid concentration was used, only the low-affinity transport system was detectable, showing that the high-affinity system was also repressed by high concentrations of the inducer.
Language of Publication
English
Unique Identifier
93377411

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MeSH Heading (Major)
Candida|EN/*ME; Carboxylic Acids|*ME; Permeases|*ME
MeSH Heading
Biological Transport|PH; Comparative Study; Dicarboxylic Acids|ME; Lactates|ME; Malates|ME; Reproducibility of Results; Substrate Specificity; Succinates|ME; Support, Non-U.S. Gov't; Tricarboxylic Acids|ME

Publication Type
JOURNAL ARTICLE
ISSN
0749-503X
Country of Publication
ENGLAND


Record 68 from database: MEDLINE
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Title
Taste responses of neurons in the nucleus of the solitary tract of awake rats: an extended stimulus array.
Author
Nakamura K; Norgren R
Address
Department of Behavioral Science, College of Medicine, Pennsylvania State University, Hershey 17033.
Source
J Neurophysiol, 1993 Sep, 70:3, 879-91
Abstract
1. Fifty-seven taste neurons were isolated in the nucleus solitary tract (NST) and tested with 15 sapid chemicals. On average, NST neurons responded well to NaCl, sucrose, monosodium L-glutamate (MSG), NaNO3, and glycine (mean = 8.2-11.0 spikes/s). Mean responses to KCl, NH4Cl, HCl, malic acid, and quinine HCl (QHCl) were low (mean = 0.7-2.9). The average responses to the other stimuli (citric acid, MgCl2, fructose, maltose, and polycose) fell between these extremes (mean = 4.3-5.1). 2. On the basis of the largest response to the four standard stimuli, the neurons were classified as follows: 15 NaCl-best, 23 sucrose-best, 17 citric acid-best, and 2 QHCl-best. 3. The NaCl-best neurons responded robustly and nearly equally to the three sodium salts (mean = 15.7-20.8) but much less so and more variably to the nonsodium, chloride salts (mean = -0.1-4.6). Sucrose-best neurons responded strongly to sucrose, glycine, and MSG (mean = 13.7-17.8), but only moderately to the other sugars (fructose and maltose) and to polycose (mean = 8.4, 9.8, and 8.8, respectively). 4. Citric acid-best neurons responded moderately to citric and malic acid (mean = 9.4 and 4.7), but less so to HCl (mean = 3.1). The two QHCl-best neurons responded moderately to QHCl and MgCl2 (mean = 12.0 and 9.5), but weakly or not at all to the other stimuli (mean = -1.1-3.1). 5. Unlike parabrachial taste neurons, none of the medullary taste cells responded specifically to Cl(-)-containing chemicals. The responses that did occur to nonsodium salts were weak and variable and often occurred in either citric acid-best or QHCl-best neurons, rather than in those that responded vigorously to sodium salts. Similar relationships have been observed in anesthetized preparations. 6. A hierarchical cluster analysis for 57 neurons across 15 stimuli produced four second-order clusters that consisted primarily of NaCl-best, sucrose-best, citric acid-best, and QHCl-best neurons, respectively. Although the analysis for neurons produced only four such clusters, a similar analysis for the 15 stimuli separated the sodium salts (NaCl and NaNO3), nonsodium salts (KCL, NH4Cl, and MGCl2, sweeteners (sucrose, maltose, fructose, and glycine), acids (citric acid and malic acid), and QHCl. 7. Monosodium glutamate activated both NaCl-best and sucrose-best neurons, but the stimulus analysis clumped it with the sodium salts.(ABSTRACT TRUNCATED AT 400 WORDS)
Language of Publication
English
Unique Identifier
94045876

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MeSH Heading (Major)
Arousal|*PH; Attention|*PH; Medulla Oblongata|*PH; Pons|*PH; Synaptic Transmission|*PH; Taste|*PH
MeSH Heading
Animal; Citrates; Cluster Analysis; Comparative Study; Evoked Potentials, Somatosensory|PH; Factor Analysis, Statistical; Male; Neural Inhibition|PH; Neurons|PH; Quinine; Rats; Rats, Sprague-Dawley; Saline Solution, Hypertonic; Sucrose; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.; Taste Threshold|PH

Publication Type
JOURNAL ARTICLE
ISSN
0022-3077
Country of Publication
UNITED STATES


Record 69 from database: MEDLINE
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Title
Effect of methotrexate (MTX) on NAD(P)+ dehydrogenases of HeLa cells: malic enzyme, 2-oxoglutarate and isocitrate dehydrogenases.
Author
Caetano NN; Campello AP; Carnieri EG; Kluppel ML; Oliveira MB
Address
Departamento de BioquÆimica da Universidade Federal do ParanÆa, Curitiba, Brasil.
Source
Cell Biochem Funct, 1997 Dec, 15:4, 259-64
Abstract
The effects of methotrexate (MTX) on oxygen uptake by permeabilized HeLa cells were evaluated. MTX did not inhibit state III respiration when the oxidizable substrate was succinate, but when the substrates were 2-oxoglutarate or isocitrate the respiration decreased about 50 per cent at 1.0 mM concentration of the drug. This effect was explained by inhibition of 2-oxoglutarate and isocitrate dehydrogenases by MTX. No effect was observed on succinate dehydrogenase. An evaluation of the effects of MTX on malic enzyme activity as measured by pyruvate plus lactate production in intact cells supplied with malate showed a decrease of about 40 per cent in metabolite production using 0.4 mM MTX. HeLa cell malic enzyme, as observed for other tumour cells, is compartmentalized in mitochondria and cytosol, and is another example of a dehydrogenase inhibited by MTX.
Language of Publication
English
Unique Identifier
98077821

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MeSH Heading (Major)
Antimetabolites, Antineoplastic|*PD; Methotrexate|*PD; Oxidoreductases|*ME
MeSH Heading
Hela Cells; Human; Isocitrate Dehydrogenase|ME; Ketoglutarate Dehydrogenase Complex|ME; Lactic Acid|ME; Malate Dehydrogenase|ME; Mitochondria|DE/EN; NADPH Dehydrogenase|ME; Oxygen Consumption|DE; Pyruvic Acid|ME; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0263-6484
Country of Publication
ENGLAND


Record 70 from database: MEDLINE
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Title
Production of succinic acid through overexpression of NAD(+)-dependent malic enzyme in an Escherichia coli mutant.
Author
Stols L; Donnelly MI
Address
Environmental Research Division, Argonne National Laboratory, Illinois 60439, USA.
Source
Appl Environ Microbiol, 1997 Jul, 63:7, 2695-701
Abstract
NAD(+)-dependent malic enzyme was cloned from the Escherichia coli genome by PCR based on the published partial sequence of the gene. The enzyme was overexpressed and purified to near homogeneity in two chromatographic steps and was analyzed kinetically in the forward and reverse directions. The Km values determined in the presence of saturating cofactor and manganese ion were 0.26 mM for malate (physiological direction) and 16 mM for pyruvate (reverse direction). When malic enzyme was induced under appropriate culture conditions in a strain of E. coli that was unable to ferment glucose and accumulated pyruvate, fermentative metabolism of glucose was restored. Succinic acid was the major fermentation product formed. When this fermentation was performed in the presence of hydrogen, the yield of succinic acid increased. The constructed pathway represents an alternative metabolic route for the fermentative production of dicarboxylic acids from renewable feedstocks.
Language of Publication
English
Unique Identifier
97355935

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MeSH Heading (Major)
Escherichia coli|*GE/*ME; Malate Dehydrogenase|*GE/IP/*ME; Succinates|*ME
MeSH Heading
Amino Acid Sequence; Base Sequence; Cloning, Molecular; Fermentation; Gene Expression; Glucose|ME; Hydrogen|ME; Kinetics; Malates|ME; Manganese|ME; Molecular Sequence Data; Pyruvic Acid|ME; Support, U.S. Gov't, Non-P.H.S.

Publication Type
JOURNAL ARTICLE
ISSN
0099-2240
Country of Publication
UNITED STATES


Record 71 from database: MEDLINE
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Title
Inducible overexpression of the FUM1 gene in Saccharomyces cerevisiae: localization of fumarase and efficient fumaric acid bioconversion to L-malic acid.
Author
Peleg Y; Rokem JS; Goldberg I; Pines O
Address
Department of Applied Microbiology, Hebrew University, Jerusalem, Israel.
Source
Appl Environ Microbiol, 1990 Sep, 56:9, 2777-83
Abstract
Cloning of the Saccharomyces cerevisiae FUM1 gene downstream of the strong GAL10 promoter resulted in inducible overexpression of fumarase in the yeast. The overproducing strain exhibited efficient bioconversion of fumaric acid to L-malic acid with an apparent conversion value of 88% and a conversion rate of 80.4 mmol of fumaric acid/h per g of cell wet weight, both of which are much higher than parameters known for industrial bacterial strains. The only product of the conversion reaction was L-malic acid, which was essentially free of the unwanted by-product succinic acid. The GAL10 promoter situated upstream of a promoterless FUM1 gene led to production and correct distribution of the two fumarase isoenzyme activities between cytosolic and mitochondrial subcellular fractions. The amino-terminal sequence of fumarase contains the mitochondrial signal sequence since (i) 92 of 463 amino acid residues from the amino terminus of fumarase are sufficient to localize fumarase-lacZ fusions to mitochondria and (ii) fumarase and fumarase-lacZ fusions lacking the amino-terminal sequence are localized exclusively in the cytosol. The possibility that both mitochondrial and cytosolic fumarases are derived from the same initial translation product is discussed.
Language of Publication
English
Unique Identifier
91112716

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MeSH Heading (Major)
Fumarate Hydratase|BI/*GE; Genes, Fungal|*; Saccharomyces cerevisiae|*GE/ME
MeSH Heading
Cloning, Molecular; Enzyme Induction; Fumarates|ME; Gene Expression; Malates|ME; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0099-2240
Country of Publication
UNITED STATES


Record 72 from database: MEDLINE
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Title
Regulation of malic-enzyme-gene expression by cAMP and retinoic acid in differentiating brown adipocytes.
Author
Hernandez A; Garcia Jimenez C; Santisteban P; Obregon MJ
Address
Instituto de Investigaciones BiomÆedicas, C. S. I. C., Madrid, Spain.
Source
Eur J Biochem, 1993 Jul, 215:2, 285-90
Abstract
Brown adipose tissue (BAT) is composed of highly specialized cells, whose main function is to produce heat under adrenergic stimulation, uncoupling oxidative phosphorylation. For this function, lipogenesis must be accurately regulated. Malic enzyme has a central role in lipogenesis and is strongly expressed in brown adipocytes. In this work, we study the modulation by adrenergic stimuli, cAMP effectors and retinoic acid on the induction produced by insulin and 3,5,3'-triiodothyronine on malic-enzyme-gene expression. Primary cultures of differentiating brown adipocytes have been used. The results obtained demonstrate that physiological doses of norepinephrine do not modify malic-enzyme mRNA levels when acting alone, but considerably reduce the induction produced by insulin, 3,5,3'-triiodothyronine or both together. Other cAMP inducers such as glucagon, forskolin or 8-bromo-cAMP, greatly inhibit both, basal and 3,5,3'-triiodothyronine-induced malic-enzyme-gene gene expression. Retinoic acid abolishes basal and also inhibits 3,5,3'-triiodothyronine-induced malic-enzyme-gene expression.
Language of Publication
English
Unique Identifier
93345514

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MeSH Heading (Major)
Adipose Tissue|CY/DE/*EN; Cyclic AMP|*PH; Gene Expression Regulation, Enzymologic|*DE; Malate Dehydrogenase|BI/*GE; Tretinoin|*PD
MeSH Heading
Animal; Cell Differentiation; Cells, Cultured; Forskolin|PD; Glucagon|PD; Insulin|PD; Norepinephrine|PD; Rats; RNA, Messenger|GE/ME; Support, Non-U.S. Gov't; Triiodothyronine|PD; 8-Bromo Cyclic Adenosine Monophosphate|PD

Publication Type
JOURNAL ARTICLE
ISSN
0014-2956
Country of Publication
GERMANY


Record 73 from database: MEDLINE
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Title
Low-dose almitrine bismesylate enhances hypoxic pulmonary vasoconstriction in closed-chest dogs.
Author
Chen L; Miller FL; Clarke WR; Clergue FX; Marshall C; Marshall BE
Address
Center for Research in Anesthesia, University of Pennsylvania School of Medicine, Philadelphia 19104.
Source
Anesth Analg, 1990 Nov, 71:5, 475-83
Abstract
The effect of almitrine bismesylate on the hypoxic pulmonary vasoconstrictor response was studied in six closed-chest dogs anesthetized with pentobarbital and paralyzed with pancuronium. The right lung was ventilated continuously with 100% O2; the left lung was ventilated either with 100% O2 ("hyperoxia") or with an hypoxic gas mixture ("hypoxia": end-tidal oxygen tension = 60.3 +/- 0.6 mm Hg). On two consecutive days, each dog received either almitrine (Vectarion, Servier Lab) or malic acid. Consecutive almitrine doses of 0.003, 0.03, 0.3, and 3.0 micrograms.kg-1.min-1, or the equivalent volumes of malic acid without almitrine, were administered intravenously as a constant peripheral infusion for 15 min. Percent blood flow to each lung was calculated based on a variation of the traditional shunt equation. The change in percent left lung blood flow (delta %QL-VA) increased significantly between the hypoxia-no drug and the hypoxia-almitrine (3.0 micrograms.kg-1.min-1) phase. No significant changes occurred during the other almitrine doses or the respective malic acid control phases. The change in arterial oxygen tension (delta PaO2) also increased significantly between the hypoxia-no drug and the hypoxia-almitrine (3.0 micrograms.kg-1.min-1) phase. No significant changes occurred during the other almitrine doses or the respective malic acid control phases. It is concluded that in dogs low-dose almitrine enhances hypoxic pulmonary vasoconstriction and that this enhancement is dose-related.
Language of Publication
English
Unique Identifier
91023507

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MeSH Heading (Major)
Almitrine|*AD; Anoxia|*PP; Lung|*BS; Vasoconstriction|*DE/PH
MeSH Heading
Animal; Comparative Study; Dogs; Dose-Response Relationship, Drug; Female; Infusions, Intravenous; Malates|AD; Stimulation, Chemical; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.

Publication Type
JOURNAL ARTICLE
ISSN
0003-2999
Country of Publication
UNITED STATES


Record 74 from database: MEDLINE
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Title
C4 acid decarboxylation and photosynthesis in bundle sheath cells of NAD-malic enzyme-type C4 plants: mechanism and the role of malate and orthophosphate.
Author
Furbank RT; Agostino A; Hatch MD
Address
CSIRO Division of Plant Industry, Canberra ACT, Australia.
Source
Arch Biochem Biophys, 1990 Feb, 276:2, 374-81
Abstract
The mechanism and possible regulation of C4 acid decarboxylation in NAD-malic enzyme-type C4 plants was studied using isolated bundle sheath cells and mitochondria from Panicum miliaceum. Rates of C4 acid-dependent photosynthetic O2 evolution equalled those observed with saturating NaHCO3; the rates ranged from 3 to 5 mumol min-1 (mg chlorophyll)-1. C4 acid-dependent O2 evolution required the addition of aspartate and 2-oxoglutarate (as a source of oxaloacetate) and also malate and orthophosphate. C4 acid decarboxylation by both isolated cells and mitochondria, measured as pyruvate production, also required all four of these components. The scheme previously proposed to account for aspartate decarboxylation in NAD-malic enzyme-type C4 plants does not envisage a role for externally derived malate. However, the mandatory requirement for malate (with orthophosphate), together with the observation that C4 acid decarboxylation is blocked by an inhibitor of the mitochondrial dicarboxylate transporter, suggests that a net flux of malate from outside the mitochondria is required to sustain this process. Arsenate was found to substitute for orthophosphate favoring a role for orthophosphate in malate transport rather than a metabolic one. The results are discussed in terms of likely mitochondrial metabolite transport mechanisms and regulation of the C4 acid decarboxylation process.
Language of Publication
English
Unique Identifier
90165430

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MeSH Heading (Major)
Carboxylic Acids|*ME; Malate Dehydrogenase|*ME; Malates|*ME/PD; Phosphates|*ME; Photosynthesis|*; Plants|CY/EN/*ME
MeSH Heading
Cytosol|ME; Kinetics; Mitochondria|ME; Models, Biological; NAD|ME; Pyruvates|ME; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0003-9861
Country of Publication
UNITED STATES


Record 75 from database: MEDLINE
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Title
Cloning and nucleotide sequence of a full-length cDNA encoding Ascaris suum malic enzyme.
Author
Kulkarni G; Cook PF; Harris BG
Address
Department of Biochemistry & Molecular Biology, Texas College of Osteopathic Medicine/University of North Texas, Fort Worth 76107.
Source
Arch Biochem Biophys, 1993 Jan, 300:1, 231-7
Abstract
The nucleotide sequence of a full-length cDNA encoding NAD(+)-malic enzyme from the parasitic nematode Ascaris suum was determined. The entire sequence of 2269 bases comprises a 5'-leader, a single open reading frame of 1851 bases, and the complete 3'-noncoding region of 340 bases. The first 12 amino acids of the translated sequence are hydrophobic, typical of mitochondrial translocation signals, and do not appear in the purified mature protein. The mature protein contains 605 amino acids and has a molecular mass of 68,478 Da. The amino acid sequences of tryptic peptides from the purified protein and also the N-terminal sequence show excellent correspondence with the translated nucleotide sequence. Comparison of the amino acid sequence of the ascarid protein with the human and rat liver NAD(+)-malic enzymes reveals highly conserved regions interrupted with long stretches of lesser homologous sequences. Structural motifs such as the putative nucleotide binding domains and also the malate binding site are clearly identified by alignment of the three protein sequences.
Language of Publication
English
Unique Identifier
93143319

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MeSH Heading (Major)
Ascaris suum|*EN/*GE; DNA|*GE; Malate Dehydrogenase|*GE
MeSH Heading
Amino Acid Sequence; Animal; Base Sequence; Cloning, Molecular; Comparative Study; Gene Library; Human; Mice; Molecular Sequence Data; Peptide Fragments|IP; Rats; Sequence Homology, Amino Acid; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.

Publication Type
JOURNAL ARTICLE
ISSN
0003-9861
Country of Publication
UNITED STATES


Record 76 from database: MEDLINE
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Title
Changes in the hepatic levels of messenger ribonucleic acid for malic enzyme during induction by thyroid hormone or diet.
Author
Towle HC; Mariash CN; Oppenheimer JH
Address
Source
Biochemistry, 1980 Feb, 19:3, 579-85
Abstract
Levels of hepatic messenger ribonucleic acid (mRNA) for malic enzyme [L-malate:NADP oxidoreductase (decarboxylating), EC 1.1.1.40] were quantitated in different dietary and hormonal states of the rat. Polysomal or total cellular poly(A)-containing RNA was translated in the rabbit reticulocyte lysate system, which had been treated to reduce endogenous mRNA activity. The relative level of incorporation of radiolabeled amino acid into malic enzyme was determined by immunoprecipitation with antibody to malic enzyme and formaldehyde-fixed Staphylococcus aureus (Cowens I strain) as an immunoadsorbent. The immunoprecipitated product comigrated with purified malic enzyme on sodium dodecyl sulfate--polyacrylamide gel electrophoresis. No malic enzyme was detected when nonspecific antisera or an excess of unlabeled malic enzyme was added during immunoprecipitation. The level of malic enzyme mRNA was found to markedly increase relative to euthyroid, chow-fed rats when the animal was either fed a high carbohydrate, fat-free diet or made hyperthyroid. Animals receiving both treatments had a further increase in mRNA activity to a level which was approximately 0.2% of the total incorporation of [3H]leucine. Levels of malic enzyme activity and the relative rate of synthesis were found to increase roughly in proportion to mRNA levels in these three states. Thus, the induction of malic enzyme by thyroid hormone or high carbohydrate, fat-free diet is due largely to an increase in the mRNA coding for this enzyme.
Language of Publication
English
Unique Identifier
80130551

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MeSH Heading (Major)
Dietary Carbohydrates|*PD; Liver|DE/*EN; Malate Dehydrogenase|*BI; RNA, Messenger|*ME; Translation, Genetic|*DE; Triiodothyronine|*PD
MeSH Heading
Animal; Enzyme Induction|DE; Hyperthyroidism|EN; Male; Rabbits; Rats; Reticulocytes|ME; Support, U.S. Gov't, P.H.S.

Publication Type
JOURNAL ARTICLE
ISSN
0006-2960
Country of Publication
UNITED STATES


Record 77 from database: MEDLINE
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Title
Relationship of malic enzyme activity to fatty acid synthesis and the pathways of glucose catabolism in developing rat liver.
Author
Madvig P; Abraham S
Address
Source
J Nutr, 1980 Jan, 110:1, 90-9
Abstract
The rates of fatty acid synthesis and the activity of several enzymes involved in lipid and carbohydrate metabolism were determined in livers from fetal, suckling, weanling and maternal rats. An estimate of the proportion of glucose catabolized via the pentose phosphate cycle and the Embden-Meyerhoff pathway was made using 14C- and 3H-labeled glucose. The contribution of pentose phosphate cycle-generated reducing equivalents to fatty acid synthesis was assessed using glucose-3-3H. Developmental changes in the activity of hepatic malic enzyme were not related to developmental changes in the rate of fatty acid synthesis as might be expected if this enzyme functioned to provide NADPH for fatty acid synthesis. Malic enzyme activity did not correlate with pentose phosphate cycle activity or with utilization for fatty acid synthesis of NADPH generated via this pathway.
Language of Publication
English
Unique Identifier
80117244

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MeSH Heading (Major)
Fatty Acids|*BI; Glucose|*ME; Liver|GD/*ME; Malate Dehydrogenase|*ME
MeSH Heading
Acetates|ME; Aging; Animal; Diet; Female; Fetus; Lactation; Male; Pentosephosphates|ME; Pregnancy; Rats; Support, U.S. Gov't, P.H.S.

Publication Type
JOURNAL ARTICLE
ISSN
0022-3166
Country of Publication
UNITED STATES


Record 78 from database: MEDLINE
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Title
Effects of dietary proteins on lipogenic enzymes in rat liver.
Author
Iritani N; Nagashima K; Fukuda H; Katsurada A; Tanaka T
Address
Source
J Nutr, 1986 Feb, 116:2, 190-7
Abstract
When fasted rats were fed fat-free diets containing various sources of protein for 3 d, the activities of liver glucose-6-phosphate dehydrogenase, malic enzyme, acetyl-CoA carboxylase and fatty acid synthetase were markedly lower in rats fed soybean protein or gluten than in those fed casein or fish protein. Since malic enzyme mRNA activity was not low in the soybean protein-fed animals, the translation of malic enzyme appears to be suppressed by dietary soybean protein. The incorporation of tritiated water into liver fatty acids was significantly lower in animals fed soybean protein than in those fed casein. The triglyceride levels in plasma and especially in liver were also lower in the groups fed soybean and gluten than in the groups fed casein and fish. In addition, when dietary soybean protein was replaced with amino acids to simulate casein or soybean protein, the effects on the levels of lipogenic enzymes were still found but were not as great. Thus, some effects can be ascribed to the protein itself and some to the amino acid composition of the diet.
Language of Publication
English
Unique Identifier
86114305

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MeSH Heading (Major)
Dietary Proteins|*PD; Liver|*EN/ME
MeSH Heading
Acetyl-CoA Carboxylase|ME; Amino Acids|PD; Animal; Caseins|PD; Dietary Fats|AD; Fatty Acid Synthetase Complex|ME; Fatty Acids|ME; Fish Products; Glucosephosphate Dehydrogenase|ME; Gluten|PD; Malate Dehydrogenase|ME; Male; Rats; Rats, Inbred Strains; RNA, Messenger|GE; Soybeans; Translation, Genetic; Triglycerides|ME; Vegetable Proteins|PD

Publication Type
JOURNAL ARTICLE
ISSN
0022-3166
Country of Publication
UNITED STATES


Record 79 from database: MEDLINE
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Title
Regulation of gene expression for lipogenic enzymes in the liver and adipose tissue of hereditary hypertriglyceridemic, insulin-resistant rats: effect of dietary sucrose and marine fish oil.
Author
Seböková E; Klimes I; Gasperíková D; Bohov P; Langer P; Lavau M; Clandinin MT
Address
Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovak Republic. sebok@uee.savba.sk
Source
Biochim Biophys Acta, 1996 Sep, 1303:1, 56-62
Abstract
Hypertriglyceridemia is closely linked to insulin resistance. Increased dietary intake of n-3 polyunsaturated fatty acids reverses both hypertriglyceridemia and insulin resistance. To evaluate molecular mechanisms responsible for the hypotriglyceridemic effects of n-3 polyunsaturated fatty acids, the expression of genes for lipogenic enzymes in liver and white and brown adipose tissue was estimated in hereditary hypertriglyceridemic rats which underwent an euglycemic hyperinsulinemic clamp. Before the clamp, animals were fed a basal or a high (63%) sucrose diet with or without fish oil for two weeks. Results were compared to data obtained from control animals subjected to the identical protocol. In hereditary hypertriglyceridemic rats, gene expression for malic enzyme was increased in liver and in brown adipose tissue but not in white adipose tissue. The high sucrose diet raised malic enzyme mRNA levels in liver of both hereditary hypertriglyceridemic and control rats, and this effect was more pronounced in brown adipose tissue. Supplementing the high sucrose diet with fish oil led to a suppression of malic enzyme gene expression in liver and brown adipose tissue of control rats. However, this inhibitory effect was not as pronounced in the hereditary hypertriglyceridemic rats. Raised levels of fatty acid synthase mRNA in liver and brown adipose tissue of control rats fed high sucrose diet were suppressed by consumption of diet high in n-3 fatty acids. On the other hand, in hereditary hypertriglyceridemic rats fed high sucrose diet, fish oil supplementation failed to suppress increased levels of fatty acid synthase mRNA in liver and in brown adipose tissue. It appears that hereditary hypertriglyceridemic rats have elevated levels of mRNA for lipogenic enzymes in liver and brown adipose tissue and dietary control leading to an alteration of hypertriglyceridemia influences gene expression of lipogenic enzymes only under special dietary circumstances.
Language of Publication
English
Unique Identifier
96413699

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MeSH Heading (Major)
Adipose Tissue|*EN; Diet|*; Gene Expression Regulation, Enzymologic|*; Hypertriglyceridemia|*CN/EN; Lipids|*BI; Liver|*EN
MeSH Heading
Animal; Antilipemic Agents|PD; Comparative Study; Dietary Carbohydrates|PD; Dietary Fats, Unsaturated|PD; Fatty Acid Synthetase Complex|BI; Fish Oils|PD; Glucose Clamp Technique; Insulin Resistance; Malate Dehydrogenase|BI; Male; Rats; Rats, Mutant Strains; Sucrose|PD; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0006-3002
Country of Publication
NETHERLANDS


Record 80 from database: MEDLINE
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Title
Duck liver malic enzyme: sequence of a tryptic peptide containing the cysteine residue labeled by the substrate analog bromopyruvate.
Author
Satterlee J; Hsu RY
Address
Health Science Center, State University of New York, Syracuse.
Source
Biochim Biophys Acta, 1991 Sep, 1079:3, 247-52
Abstract
Malic enzyme of duck liver is alkylated by bromopyruvate with half-of-the-sites stoichiometry, and with accompanying loss of oxidative decarboxylase and enhancement of pyruvate reductase activities as was previously shown for the pigeon enzyme (Hsu, R.Y. (1982) Mol. Cell. Biochem. 43, 3-26). In the present work, the alkylated enzyme is shown to bind NADPH, but not L-malate in the presence of MnCl2, indicating impairment of the enzyme site for the substrate and/or divalent metal. The enzyme was differentially labeled by 3-bromo-1-[14C]-pyruvate and digested with TPCK-treated trypsin. Two peptides bearing the susceptible residue were purified by high-performance liquid chromatography and sequenced. Peptide II has the sequence of FMPIVYTPTVGLAXQQYGLAFR, corresponding to residues 86-107 (temporary numbering) of the duck enzyme; cysteine-99(x) is not detected, indicating that it is the target of modification by bromopyruvate. Peptide I is a truncated form of peptide II lacking five amino acid residues at the C-terminal. Cysteine-99 is conserved in malic enzymes from duck, rat, mouse, maize, human, Flaveria trinervia and Bacillus stearothermophilus.
Language of Publication
English
Unique Identifier
92002141

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MeSH Heading (Major)
Liver|*EN; Malate Dehydrogenase|GE/IP/*ME; Pyruvates|*ME
MeSH Heading
Affinity Labels; Amino Acid Sequence; Animal; Comparative Study; Ducks; Kinetics; Molecular Sequence Data; Peptide Fragments|IP/ME; Sequence Homology, Nucleic Acid; Spectrometry, Fluorescence; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.; Trypsin|ME

Publication Type
JOURNAL ARTICLE
ISSN
0006-3002
Country of Publication
NETHERLANDS


Record 81 from database: MEDLINE
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Title
The NADPH-producing pathways (pentose phosphate and malic enzyme) are regulated by the NADPH consumption in rat mammary gland.
Author
Revilla E; Fabregat I; Santa María C; Machado A
Address
Departamento de BioquÆimica, Facultad de Farmacia, Universidad de Sevilla, Spain.
Source
Biochem Int, 1987 May, 14:5, 957-62
Abstract
We have studied the changes in the activity of the pentose phosphate cycle and the malic enzyme produced by the activation or inhibition of different NADPH-consuming pathways. Kynurenate, an acetyl-CoA-carboxylase inhibitor produced a decrease in the flux through the NADPH-producing pathways pentose phosphate cycle and malic enzyme. Acini (isolated from mammary gland) incubated in the presence of ter-butyl-hydroperoxide, a compound which is metabolized via a NADPH-consuming pathway, showed a substantial increase in the pentose phosphate cycle and the malic enzyme pathways.
Language of Publication
English
Unique Identifier
88309169

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MeSH Heading (Major)
Malate Dehydrogenase|*ME; Mammae|EN/*ME; NADP|AI/*ME; Pentosephosphate Pathway|*
MeSH Heading
Animal; Enzyme Activation; Female; In Vitro; Kynurenic Acid|PD; Peroxides|PD; Rats; Rats, Inbred Strains; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0158-5231
Country of Publication
AUSTRALIA


Record 82 from database: MEDLINE
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Title
Levels of mRNAs coding for lipogenic enzymes in rat lung upon fasting and refeeding and during perinatal development [published erratum appears in Biochim Biophys Acta 1990 Feb 6;1042(2):269]
Author
Batenburg JJ; Whitsett JA
Address
Laboratory of Veterinary Biochemistry, Utrecht University, The Netherlands.
Source
Biochim Biophys Acta, 1989 Dec, 1006:3, 329-34
Abstract
The relative amounts of mRNAs coding for fatty-acid synthase (EC 2.3.1.85), acetyl-CoA carboxylase (EC 6.4.1.2), ATP citrate lyase (EC 4.1.3.8) and malic enzyme (EC 1.1.1.40) were determined in lungs and livers of adult rats that were normally fed, starved for 48 h or starved for 48 h and subsequently refed for 72 h with a carbohydrate-rich, fat-free diet. In the liver, starvation caused a small decrease in the relative abundance of the mRNAs which was not statistically significant. Subsequent refeeding caused a statistically significant increase in mRNAs for all of the enzymes studied. In the lung, no significant changes were found, indicating that the regulation of the abundance of mRNAs encoding the lipogenic enzymes in the lung differs from that in the liver. In the developing rat lung, mRNA for fatty-acid synthase increased 3-fold in abundance between fetal days 18 and 20 and decreased directly after birth (at day 22 of gestation). A similar pattern was observed for ATP citrate lyase mRNA. The level of acetyl-CoA carboxylase mRNA decreased significantly after birth. These observations indicate that in perinatal rat lungs, pretranslational regulation is involved in the control of the synthesis of these enzymes. The abundance of acetyl-CoA carboxylase mRNA did not change in the prenatal period, a time during which the specific activity of this enzyme increases. This lack of correlation between the specific activity of acetyl-CoA carboxylase and the abundance of its mRNA may indicate that translational regulation of the synthesis of the enzyme or post-synthetic regulatory effects on enzyme molecules are involved in the control of this enzyme in the prenatal period. No changes in the abundance of lung malic enzyme mRNAs were observed throughout the perinatal period.
Language of Publication
English
Unique Identifier
90089390

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MeSH Heading (Major)
Animals, Newborn|*ME; Fasting|*; Food|*; Lipids|*BI; Lung|EM/*EN/GD; RNA, Messenger|*ME
MeSH Heading
Acetyl-CoA Carboxylase|GE; Animal; ATP Citrate (pro-S)-Lyase|GE; Fatty Acid Synthetase Complex|GE; Gene Expression Regulation; Gestational Age; Liver|EN; Malate Dehydrogenase|GE; Male; Nucleic Acid Hybridization; Rats; Rats, Inbred Strains; Support, Non-U.S. Gov't; Translation, Genetic

Publication Type
JOURNAL ARTICLE
ISSN
0006-3002
Country of Publication
NETHERLANDS


Record 83 from database: MEDLINE
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Title
Effects of androgens, prolactin and bromocriptine on seminal vesicular enzymes of the pyruvate malate cycle involved in lipogenesis in castrated mature monkeys, Macaca radiata.
Author
Arunakaran J; Balasubramanian K; Srinivasan N; Aruldhas MM; Govindarajulu P
Address
Department of Endocrinology, University of Madras, Taramani, India.
Source
Int J Androl, 1988 Apr, 11:2, 133-9
Abstract
The interaction of androgens and prolactin, the major factors regulating the male accessory sex organs, on the specific activity of seminal vesicular enzymes of the pyruvate/malate cycle were studied in castrated mature monkeys. Castration decreased the activity of these enzymes, including NADP+ isocitrate dehydrogenase, ATP citrate lyase, malate dehydrogenase, malic enzyme and fatty acid synthase. Testosterone propionate (TP)/dihydrotestosterone given as replacement to castrates increased the activity of all these enzymes, except for malate dehydrogenase. Prolactin restored normal activity of ATP citrate lyase, malic enzyme and fatty acid synthase but not of isocitrate dehydrogenase and malate dehydrogenase (MDH). Prolactin had a specific control over MDH. Moreover, when prolactin was combined with androgens a further stimulatory influence was observed on fatty acid synthase activity. In order to prove the direct influence of prolactin on enzymes of the pyruvate/malate cycle, bromocriptine was administered and this inhibited all of the enzymes. Thus prolactin was found to have a direct, as well as a synergistic, action with androgens on enzymes of the pyruvate/malate cycle in the seminal vesicles of monkeys.
Language of Publication
English
Unique Identifier
88227020

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MeSH Heading (Major)
Androgens|*PD; Bromocriptine|*PD; Lipids|*BI; Prolactin|*PD; Seminal Vesicles|DE/*EN
MeSH Heading
Animal; ATP Citrate (pro-S)-Lyase|ME; Fatty Acid Synthetase Complex|ME; Isocitrate Dehydrogenase|ME; Macaca radiata; Malates|ME; Male; Orchiectomy; Pyruvates|ME; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0105-6263
Country of Publication
DENMARK


Record 84 from database: MEDLINE
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Title
Effects of dietary nutrients on lipogenic enzyme and mRNA activities in rat liver during induction.
Author
Katsurada A; Iritani N; Fukuda H; Noguchi T; Tanaka T
Address
Source
Biochim Biophys Acta, 1986 Jul, 877:3, 350-8
Abstract
By feeding a carbohydrate diet (without protein) to fasted rats, malic enzyme mRNA activity in the liver was increased to the level in rats fed a carbohydrate and protein diet, whereas the enzyme activity itself was increased to 60% of that level. It appears that malic enzyme mRNA activity was increased by dietary carbohydrate, while dietary protein contributed to an increase in the translation of mRNA. In the animals fed carbohydrate without protein, glucose-6-phosphate dehydrogenase mRNA activity increased to 50% of the level in rats fed the carbohydrate and protein diet, whereas the enzyme activity increased to only 25%. By feeding a protein diet (without carbohydrate), glucose-6-phosphate dehydrogenase activity increased to 65% of the level in rats fed both carbohydrate and protein. This enzyme induction appears to be more dependent on protein than carbohydrate. With the carbohydrate diet, acetyl-CoA carboxylase was induced up to the level in the carbohydrate and protein diet group, whereas fatty acid synthetase was induced to only 33%. Acetyl-CoA carboxylase induction appears to be carbohydrate dependent. On the other hand, isotopic leucine incorporation studies showed that the magnitudes of the enzyme inductions caused by the dietary nutrients should be ascribed to the enzyme synthesis rates rather than the degradation. By fat feeding, the mRNA activities of malic enzyme and glucose-6-phosphate dehydrogenase were markedly decreased along with the enzyme induction. Fat appears to reduce these enzyme inductions before the translation of mRNA.
Language of Publication
English
Unique Identifier
86270019

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MeSH Heading (Major)
Dietary Carbohydrates|*PD; Dietary Fats|*PD; Dietary Proteins|*PD; Lipids|*BI; Liver|*EN; RNA, Messenger|*AN
MeSH Heading
Acetyl-CoA Carboxylase|BI; Animal; Enzyme Induction; Fatty Acid Synthetase Complex|BI; Glucosephosphate Dehydrogenase|BI/GE; Malate Dehydrogenase|BI/GE; Male; Rats; Rats, Inbred Strains; Time Factors

Publication Type
JOURNAL ARTICLE
ISSN
0006-3002
Country of Publication
NETHERLANDS


Record 85 from database: MEDLINE
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Title
CO2 is the inorganic carbon substrate of NADP malic enzymes from Zea mays and from wheat germ.
Author
Häusler RE; Holtum JA; Latzko E
Address
Source
Eur J Biochem, 1987 Mar, 163:3, 619-26
Abstract
NADP malic enzyme (EC 1.1.1.40) was extracted and partially purified from the green leaves of Zea mays var. Felix and from wheat germ. The active inorganic carbon species for both enzymes was, in contrast to an earlier report, CO2 not HCO3-. The apparent Km, CO2 for the maize enzyme was 1.2 mM and the apparent Km, CO2 for the wheat germ preparation was 4.2 mM under conditions of substrate saturation, pH 7.3 and 17 degrees C. These observations support the views that CO2, rather than HCO3- as has been suggested, is produced in bundle-sheath chloroplasts and that the reaction mechanism catalysed by plant cytosolic and chloroplastic NADP malic enzymes is similar to that proposed for avian NADP malic enzymes.
Language of Publication
English
Unique Identifier
87161864

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MeSH Heading (Major)
Carbon Dioxide|*ME; Malate Dehydrogenase|*ME; NADP|*ME; Plants|*EN
MeSH Heading
Carbonic Acid|ME; Corn; Hydrogen-Ion Concentration; Mathematics; Time Factors; Wheat

Publication Type
JOURNAL ARTICLE
ISSN
0014-2956
Country of Publication
GERMANY, WEST


Record 86 from database: MEDLINE
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Title
Hormonal and dietary regulation of hepatic enzymes in tumor-bearing rats.
Author
Greengard O; Cayanis E
Address
Source
Cancer Res, 1983 Apr, 43:4, 1575-80
Abstract
Enzymes in the histologically normal liver of hosts of mammary carcinomas were examined for their responsiveness to endocrine and dietary modulations. Treatments with the developmental stimuli of alanine aminotransferase (glucocorticoids) and of pyruvate kinase (thyroid hormone) which had no effect in control adult rats raised the levels of these enzymes in the tumor-bearing rats. The latter also showed a greater percentage of increase in malic enzyme upon thyroid hormone administration than did control animals. The tumor-induced increase in hexokinase remained unaltered by the various dietary treatments; enzymes at subnormal levels were raised (glucokinase, malic enzymes, and pyruvate kinase) or further decreased (alanine aminotransferase and ornithine aminotransferase) by excessive carbohydrate intake in immature and adult experimental rats. The normal upsurge of glucokinase and malic enzyme upon weaning to the standard solid diet (from the relatively low-carbohydrate-containing milk) was prevented by cancerous growth in the organism. Similarly, the standard diet, which reversed within 2 days the partial loss of these enzymes in normal adult rats fasted for 48 hr, had no restorative effect on the essentially complete loss of the glucokinase and the very low malic enzyme activity in the fasted tumor bearers. The results suggest that failure in the dietary adaptations of hepatic enzymes as well as diminutions of their basal levels contributes to the clinically observed abnormalities in the glucose metabolism of cancer subjects.
Language of Publication
English
Unique Identifier
83155230

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MeSH Heading (Major)
Alanine Transaminase|*ME; Glucokinase|*ME; Hexokinase|*ME; Liver|DE/*EN; Malate Dehydrogenase|*ME; Mammary Neoplasms, Experimental|*EN; Ornithine-Oxo-Acid Transaminase|*ME; Pyruvate Kinase|*ME; Transaminases|*ME
MeSH Heading
Animal; Histocytochemistry; Hydrocortisone|PD; Rats; Rats, Inbred F344; Support, U.S. Gov't, P.H.S.; Thyroxine|PD; Triiodothyronine|PD

Publication Type
JOURNAL ARTICLE
ISSN
0008-5472
Country of Publication
UNITED STATES


Record 87 from database: MEDLINE
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Title
The regulation of glucose and pyruvate formation from glutamine and citric-acid-cycle intermediates in the kidney cortex of rats, dogs, rabbits and guinea pigs.
Author
Watford M; Vinay P; Lemieux G; Gougoux A
Address
Source
Biochem J, 1980 Jun, 188:3, 741-8
Abstract
The suppression by 3-mercaptopicolinate of gluconeogenesis from glutamine or 2-oxoglutarate in rat or dog kidney tubules did not affect the amount of these substrates undergoing complete oxidation. Furthermore, 3-mercaptopicolinate caused an accumulation of lactate in dog tubules. 3-Mercaptopicolinate abolished both gluconeogenesis and substrate oxidation in tubules from rabbit and guinea-pig kidney. These results imply the presence of an alternative pathway to phosphoenolpyruvate carboxykinase/pyruvate kinase for the production of pyruvate from citric-acid-cycle intermediates in the kidney cortex of rats and dogs but not in that of rabbits or guinea pigs. Oxaloacetate decarboxylase (present in the kidney cortex of all four species) or 'malic' enzyme (present in rat and dog but absent in rabbit and guinea-pig kidney cortex) could function in this role. Our observations indicate that 'malic' enzyme is probably implicated in this phenomenon. The lactate production observed in dog tubules in the presence of 3-mercaptopicolinate can be suppressed when aspartate formation is inhibited by 2-amino-4-methoxy-trans-but-3-enoic acid. This suggests that the provision of cytosolic NADH from citric-acid-cycle intermediates is facilitated by accumulation of aspartate acting as a 'sink' for cytosolic oxaloacetate.
Language of Publication
English
Unique Identifier
81133445

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MeSH Heading (Major)
Citric Acid Cycle|*; Gluconeogenesis|*/DE; Glutamine|*ME; Kidney Cortex|DE/*ME; Pyruvates|*BI
MeSH Heading
Animal; Comparative Study; Dogs; Guinea Pigs; In Vitro; Ketoglutaric Acids|ME; Kidney Tubules|DE/ME; Lactates|ME; Picolinic Acids|PD; Rabbits; Rats; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0006-2936
Country of Publication
ENGLAND


Record 88 from database: MEDLINE
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Title
Insulin-mediated post-transcriptional regulation of hepatic malic enzyme and albumin mRNAs.
Author
Davis BB; Magge S; Mucenski CG; Drake RL
Address
Department of Anatomy and Cell Biology, University of Cincinnati College of Medicine, Ohio 45267-0521.
Source
Biochem Biophys Res Commun, 1988 Aug, 154:3, 1081-7
Abstract
Livers of insulin-treated diabetic rats accumulate albumin and malic enzyme mRNAs at very different rates. We now report that in normal rats insulin directs a specific increase in malic enzyme mRNA, while albumin mRNA levels remain unaltered. These studies support the contention that insulin regulates the accumulation of hepatic mRNAs in a highly specific manner. To evaluate whether or not albumin and malic enzyme mRNA levels are determined by altered rates of transcription, in vitro transcription assays were performed. The results of these studies demonstrate that increased malic enzyme mRNA levels in insulin-treated normal rats and increased malic enzyme and albumin mRNA levels in insulin-treated diabetic rats do not involve altered rates of transcription of the genetic sequences encoding these proteins. For these two specific proteins, insulin mediates changes in mRNA levels by a post-transcriptional mechanism.
Language of Publication
English
Unique Identifier
88309087

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MeSH Heading (Major)
Diabetes Mellitus, Experimental|*ME; Insulin|*PD; Liver|DE/*ME; Malate Dehydrogenase|*GE; RNA Processing, Post-Transcriptional|*DE; RNA, Messenger|DE/*GE; Serum Albumin|*GE
MeSH Heading
Animal; Cell Nucleus|ME; Male; Nucleic Acid Hybridization; Rats; Rats, Inbred Strains; Reference Values; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.; Transcription, Genetic|DE

Publication Type
JOURNAL ARTICLE
ISSN
0006-291X
Country of Publication
UNITED STATES


Record 89 from database: MEDLINE
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Title
The pyruvate-proton exchange reaction of malic enzyme from pigeon liver.
Author
Bratcher SC; Hsu RY
Address
Source
Biochim Biophys Acta, 1982 Mar, 702:1, 54-60
Abstract
Malic enzyme (L-malate:NADP+ oxidoreductase (decarboxylating) EC 1.1.1.40) catalyzes the incorporation of proton from medium water into pyruvate present either as the initial substrate or as the enzyme-bound product of malate decarboxylation. In the later reaction a single proton is incorporated into the methyl group of pyruvate. The pyruvate-medium proton exchange reaction requires Mg2+, NADPH and CO2-HCO3- as cofactors. The apparent Michaelis constants of pyruvate, NADPH and CO2-HCO3- are 4.8 mM, 2 microM and approx. 9 microM, respectively. The experimentally determined incorporation of 2.5 tritium atoms from tritiated water into pyruvate indicates that all three methyl protons of this compound are stereochemically equivalent in the exchange reaction. These results are consistent with the postulated kinetic mechanism for the malate reaction (Hsu, R.Y., Lardy, H.A. and Cleland, W.W. (1967) J. Biol. Chem. 242, 5315--5322), which predicts the formation of an enolpyruvate intermediate during the reaction. The rate of malic enzyme-catalyzed detritiation of beta-tritiated pyruvate is unaffected by modification of an essential protein thiol group with 5,5'-dithiobis(2-nitrobenzoic acid) or KCN. Moreover, the native- and thiol-modified enzymes also catalyze the detritiation of beta-tritiated bromopyruvate at slower rates.
Language of Publication
English
Unique Identifier
82160971

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MeSH Heading (Major)
Liver|*EN; Malate Dehydrogenase|*ME
MeSH Heading
Affinity Labels|PD; Animal; Dithionitrobenzoic Acid|PD; Kinetics; Pigeons; Potassium Cyanide|PD; Pyruvates|PD; Support, U.S. Gov't, P.H.S.; Thiocyanates|PD; Tritium

Publication Type
JOURNAL ARTICLE
ISSN
0006-3002
Country of Publication
NETHERLANDS


Record 90 from database: MEDLINE
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Title
Hepatic lipogenesis and mobilization of peripheral fats in the formation of alcoholic fatty liver.
Author
Muramatsu M; Kuriyama K; Yuki T; Ohkuma S
Address
Source
Jpn J Pharmacol, 1981 Dec, 31:6, 931-40
Abstract
Biochemical mechanisms underlying the development of alcoholic fatty liver was investigated. Acute ethanol (EtOH) administration for 3 days by an inhalation method, and continuous EtOH treatments by feeding with liquid diet or drinking water containing EtOH induced a significant increase of hepatic triglycerides (TG). A small but significant increase of TG was also observed in the blood serum. Although hepatic acetyl CoA carboxylase activity, measured in the presence and absence of citrate, was not altered by either acute or chronic EtOH administrations, fatty acid synthetase and malic enzyme activities in the liver were increased by continuous EtOH administration, but not in the acutely EtOH-treated animals. The incorporations of [14C]palmitate and [14C]acetate into hepatic RG were also increased significantly in animals treated continuously with EtOH. The lipoprotein lipase activity in adipose tissues was activated by both acute and continuous EtOH treatments, whereas lipase activity in adipose tissues and the epinephrine-stimulated and cyclic AMP-mediated release of free fatty acid (FFA) from this tissue were not altered by these treatments. These results indicate that acute alcoholic fatty liver is caused mostly by the increased mobilization of FFA from peripheral adipose tissues via the activation of lipoprotein lipase, whereas alcoholic fatty liver induced by continuous EtOH administration involves the increased synthesis of FFA due to the activation of fatty acid synthetase and malic enzyme in the liver in addition to the increased mobilization of peripheral FFA.
Language of Publication
English
Unique Identifier
82146371

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MeSH Heading (Major)
Fatty Liver, Alcoholic|*ET; Lipid Mobilization|*; Lipids|*BI; Liver|*ME
MeSH Heading
Acetyl-CoA Carboxylase|AN; Adipose Tissue|ME; Animal; Fatty Acid Synthetase Complex|AN; Fatty Acids, Nonesterified|ME; Male; Mice; Mice, Inbred Strains; Palmitates|ME; Triglycerides|ME

Publication Type
JOURNAL ARTICLE
ISSN
0021-5198
Country of Publication
JAPAN


Record 91 from database: MEDLINE
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Title
Effects of ethanol and acetic acid on the transport of malic acid and glucose in the yeast Schizosaccharomyces pombe: implications in wine deacidification.
Author
Sousa MJ; Mota M; Leão C
Address
Department of Biology, University of Minho, Braga, Portugal.
Source
FEMS Microbiol Lett, 1995 Feb, 126:2, 197-202
Abstract
Ethanol and acetic acid, at concentrations which may occur during wine-making, inhibited the transport of L-malic acid in Schizosaccharomyces pombe. The inhibition was non-competitive, the decrease of the maximum initial velocity following exponential kinetics. Glucose transport was not significantly affected either by ethanol (up to 13%, w/v) or by acetic acid (up to 1.5%, w/v). The uptake of labelled acetic acid followed simple diffusion kinetics, indicating that a carrier was not involved in its transport. Therefore, the undissociated acid appears to be the only form that enters the cells and is probably responsible for the toxic effects. Accordingly, deacidification by Ss. pombe during wine fermentation should take place before, rather than after, the main alcoholic fermentation by Saccharomyces cerevisiae.
Language of Publication
English
Unique Identifier
95220648

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MeSH Heading (Major)
Glucose|*ME; Malates|*ME; Schizosaccharomyces|*ME
MeSH Heading
Acetic Acids|PD; Biological Transport|DE; Ethanol|PD; Fermentation; Support, Non-U.S. Gov't; Wine

Publication Type
JOURNAL ARTICLE
ISSN
0378-1097
Country of Publication
NETHERLANDS


Record 92 from database: MEDLINE
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Title
Effects of insulin and fructose on transcriptional and post-transcriptional regulation of malic enzyme synthesis in diabetic rat liver.
Author
Katsurada A; Iritani N; Fukuda H; Matsumura Y; Noguchi T; Tanaka T
Address
Tezukayama Gakuin College, Osaka, Japan.
Source
Biochim Biophys Acta, 1989 Jul, 1004:1, 103-7
Abstract
Insulin action on regulation of hepatic malic enzyme has been investigated in comparison with fructose, using streptozotocin-induced diabetic rats. Insulin-treatment caused a 2.8-fold increase in the transcriptional rate of malic enzyme (EC 1.1.1.40) after 8 h, and a 5-fold increase in the mRNA concentration of the liver. In Northern blot analysis, we demonstrated that after insulin treatment, the nuclear mRNA of malic enzyme tended to increase more rapidly than the total cellular mRNA. Therefore, it is suggested that the nuclear mRNA was primarily increased by insulin. The insulin-dependent increase of malic enzyme mRNA was blocked by cycloheximide, suggesting that synthesis of a peptide is required. On the other hand, by feeding a high-fructose diet to diabetic rats, the malic enzyme mRNA concentration was considerably increased, though with a delayed peaking in comparison with the insulin-treated animals, whereas the transcriptional rate was not significantly increased. Dietary fructose may stabilize the transcripts. Fructose increased the enzyme level far less than the mRNA level. These results suggest that insulin is required in both the translational and transcriptional regulation of malic enzyme.
Language of Publication
English
Unique Identifier
89302986

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MeSH Heading (Major)
Diabetes Mellitus, Experimental|*EN; Fructose|*PD; Insulin|*PD; Malate Dehydrogenase|*BI/GE; Protein Processing, Post-Translational|*/DE; Transcription, Genetic|*/DE
MeSH Heading
Animal; Blotting, Northern; Dietary Carbohydrates|PD; Enzyme Induction|DE; Gene Expression Regulation|DE; Male; Nucleic Acid Hybridization; Rats; Rats, Inbred Strains; RNA, Messenger|DE

Publication Type
JOURNAL ARTICLE
ISSN
0006-3002
Country of Publication
NETHERLANDS


Record 93 from database: MEDLINE
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Title
Low- and high-affinity transport systems for citric acid in the yeast Candida utilis.
Author
Cássio F; Leáo C
Address
Laboratory of Biology, University of Minho, Braga, Portugal.
Source
Appl Environ Microbiol, 1991 Dec, 57:12, 3623-8
Abstract
Citric acid-grown cells of the yeast Candida utilis induced two transport systems for citric acid, presumably a proton symport and a facilitated diffusion system for the charged and the undissociated forms of the acid, respectively. Both systems could be observed simultaneously when the transport was measured at 25 degrees C with labelled citric acid at pH 3.5 with the following kinetic parameters: for the low-affinity system, Vmax, 1.14 nmol of undissociated citric acid s-1 mg (dry weight) of cells-1, and Km, 0.59 mM undissociated acid; for the high-affinity system, Vmax, 0.38 nmol of citrate s-1 mg (dry weight) of cells-1, and Km, 0.056 mM citrate. At high pH values (above 5.0), the low-affinity system was absent or not measurable. The two transport systems exhibited different substrate specificities. Isocitric acid was a competitive inhibitor of citric acid for the high-affinity system, suggesting that these tricarboxylic acids used the same transport system, while aconitic, tricarballylic, trimesic, and hemimellitic acids were not competitive inhibitors. With respect to the low-affinity system, isocitric acid, L-lactic acid, and L-malic acid were competitive inhibitors, suggesting that all of these mono-, di-, and tricarboxylic acids used the same low-affinity transport system. The two transport systems were repressed by glucose, and as a consequence diauxic growth was observed. Both systems were inducible, and not only citric acid but also lactic acid and malic acid may induce those transport systems. The induction of both systems was not dependent on the relative concentration of the anionic form(s) and of undissociated citric acid in the culture medium.(ABSTRACT TRUNCATED AT 250 WORDS)
Language of Publication
English
Unique Identifier
92152862

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MeSH Heading (Major)
Candida|GD/*ME; Citrates|*ME
MeSH Heading
Biological Transport; Cell Membrane|ME; Diffusion; Hydrogen-Ion Concentration; Kinetics; Protons; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0099-2240
Country of Publication
UNITED STATES


Record 94 from database: MEDLINE
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Title
Nutritional and hormonal regulation of mRNA levels of lipogenic enzymes in primary cultures of rat hepatocytes.
Author
Fukuda H; Katsurada A; Iritani N
Address
Tezukayama Gakuin College, Osaka.
Source
J Biochem (Tokyo), 1992 Jan, 111:1, 25-30
Abstract
The effects of nutrients and hormones on the mRNA levels of acetyl-CoA carboxylase, fatty acid synthase, malic enzyme, and glucose 6-phosphate dehydrogenase were examined in primary cultures of rat hepatocytes during the process of induction. The addition of both glucose and insulin to the culture medium markedly enhanced the lipogenic enzyme mRNA induction due to either of them, in 16 h. Fructose or glycerol proved to be an effective substitute for glucose, suggesting that glycolytic metabolites were involved in the mRNA induction. It is remarkable that mRNA induction of acetyl-CoA carboxylase was the most sensitive to glucose and also to insulin among the lipogenic enzymes. Polyunsaturated fatty acids markedly reduced the mRNA induction of lipogenic enzymes. Dexamethasone enhanced all the lipogenic enzyme mRNA induction by insulin. On the other hand, triiodothyronine addition greatly increased the mRNA concentrations of lipogenic enzymes, but dexamethasone decreased rather than increased the mRNA induction by triiodothyronine. The effects of insulin on the induction of the lipogenic enzyme mRNAs were similar, but those of triiodothyronine were not. Triiodothyronine markedly enhanced malic enzyme mRNA induction by insulin with dexamethasone, and tended to enhance the induction of the acetyl-CoA carboxylase and fatty acid synthase mRNAs, but not that of glucose 6-phosphate dehydrogenase mRNA. It appeared that insulin and triiodothyronine synergistically enhanced lipogenic enzyme mRNA induction by glucose, but the mechanisms were different.
Language of Publication
English
Unique Identifier
92299648

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MeSH Heading (Major)
Fatty Acids|*BI; Glucose|*PD; Insulin|*PD; Liver|CY/EN/*ME; RNA, Messenger|*GE/ME
MeSH Heading
Acetyl-CoA Carboxylase|BI/GE; Animal; Cells, Cultured; Enzyme Induction; Fatty Acid Synthetase Complex|BI/GE; Glucosephosphate Dehydrogenase|BI/GE; Malate Dehydrogenase|BI/GE; Male; Rats; Rats, Inbred Strains; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0021-924X
Country of Publication
JAPAN


Record 95 from database: MEDLINE
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Title
Identification of Asp258 as the metal coordinate of pigeon liver malic enzyme by site-specific mutagenesis.
Author
Wei CH; Chou WY; Chang GG
Address
Graduate Institutes of Life Sciences and Biochemistry, National Defense Medical Center, Taipei, Taiwan, Republic of China.
Source
Biochemistry, 1995 Jun, 34:24, 7949-54
Abstract
Pigeon liver malic enzyme was inactivated by ferrous sulfate in the presence of ascorbate. Manganese and some other divalent metal ions provided complete protection of the enzyme against the Fe(2+)-induced inactivation. The inactivated enzyme was subsequently cleaved by the Fe(2+)-ascorbate system at Asp258-Ile259, which was presumably the Mn(2+)-binding site of the enzyme [Wei, C. H., Chou, W. Y., Huang, S. M., Lin, C. C., & Chang, G. G. (1994) Biochemistry 33, 7793-7936]. For identification of Asp258 as the putative metal-binding site of the enzyme, we prepared four mutant enzymes substituted at Asp258 with glutamate (D258E), asparagine (D258N), lysine (D258K), or alanine (D258A), respectively. These mutant proteins were recombinantly expressed in a bacterial expression system (pET-15b) with a stretch of histidine residues attached at the N-terminus and were successfully purified to apparent homogeneity by a single Ni-chelated affinity column. Among the four mutants, only D258E possessed 0.8% residual activity after purification; all other purified mutants had < 0.0001% residual activity in catalyzing the oxidative decarboxylation of L-malate. The D258E mutant was susceptible to inactivation by the Fe(2+)-ascorbate system, albeit with much slower inactivation rate, and was protected by the Mn2+ to a lesser extent as compared to the wild-type enzyme. None of the mutants were cleaved by the Fe(2+)-ascorbate system under conditions that cleaved the natural or wild-type enzyme at Asp258.(ABSTRACT TRUNCATED AT 250 WORDS)
Language of Publication
English
Unique Identifier
95315182

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MeSH Heading (Major)
Aspartic Acid|GE/*ME; Malate Dehydrogenase|GE/IP/*ME; Metalloproteins|GE/*ME
MeSH Heading
Amino Acids|GE/ME; Animal; Ascorbic Acid|PD; Base Sequence; Binding Sites|GE; Comparative Study; Ferrous Compounds|PD; Kinetics; Liver|EN; Magnesium|ME; Manganese|ME; Molecular Sequence Data; Mutagenesis, Site-Directed; Pigeons; Structure-Activity Relationship; Support, Non-U.S. Gov't

Publication Type
JOURNAL ARTICLE
ISSN
0006-2960
Country of Publication
UNITED STATES


Record 96 from database: MEDLINE
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Title
Effects of aging on contributions of dietary fat and triiodothyronine treatment to lipogenic enzyme induction.
Author
Fukuda H; Katsurada A; Iritani N
Address
Source
Biochim Biophys Acta, 1987 Sep, 921:1, 43-9
Abstract
Although lipogenic enzyme inductions are reduced by fat feeding, this reduction decreases with aging and is particularly detectable in the case of acetyl-CoA carboxylase and fatty acid synthetase activities. On the other hand, the fat-dependent reductions of malic enzyme and acetyl-CoA carboxylase were consistently relieved by triiodothyronine (T3) treatment. The effects of T3 treatment on these enzyme inductions were greater in 10-month-old rats than in 1-month-old rats, while the carbohydrate-dependent induction and the fat-dependent reduction of the enzymes decreased with aging. In these animals, alterations in malic enzyme mRNA translational activities were roughly in parallel to the enzyme activities. Therefore, the age-dependent alterations in effects of T3 treatment and fat on malic enzyme induction do not appear to occur in post-translation.
Language of Publication
English
Unique Identifier
87299760

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MeSH Heading (Major)
Aging|*; Dietary Fats|*PD; Lipids|*BI; Triiodothyronine|*PD
MeSH Heading
Acetyl-CoA Carboxylase|BI; Adipose Tissue|AN; Animal; Body Weight; Enzyme Induction; Fatty Acid Synthetase Complex|BI; Glucosephosphate Dehydrogenase|BI; Liver|EN; Malate Dehydrogenase|BI; Male; Rats; Rats, Inbred Strains; Triglycerides|ME

Publication Type
JOURNAL ARTICLE
ISSN
0006-3002
Country of Publication
NETHERLANDS


Record 97 from database: MEDLINE
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Title
Cloning of cDNA sequences for murine malic enzyme and the identification of aberrantly large malic enzyme mRNA in MOD-1 null mice.
Author
Sul HS; Wise LS; Brown ML; Rubin CS
Address
Source
J Biol Chem, 1984 Jan, 259:1, 555-9
Abstract
Polysomes containing cytosolic malic enzyme mRNA and malic enzyme nascent chains were complexed with specific antibodies and purified by chromatography on protein A-Sepharose. When poly(A+) mRNA derived from the immunoselected polysomes was translated in vitro, full length malic enzyme (subunit Mr = 58,000) accounted for a significant fraction (approximately 20%) of the polypeptides synthesized. Double-stranded cDNA, synthesized using partially purified malic enzyme mRNA as a template, was inserted into pBR 322 and cloned. Twenty-five candidate malic enzyme cDNA clones were identified by differential hybridization. Four clones were studied further and each of these was shown to have malic enzyme cDNA sequences by hybrid-selected translation and specific immunoprecipitation. Plasmid pME1, which contains a 1400-base pair insert, hybridized to two mouse liver malic enzyme mRNAs with lengths of 2300 and 3500 bases. Similar analyses were performed on liver mRNAs isolated from MOD-1 mutant mice which lack cytosolic malic enzyme activity. These Northern blots disclosed a pair of aberrantly large malic enzyme mRNAs with lengths of 2800 and 4000 bases. Furthermore, anti-malic enzyme antibodies exclusively precipitated a polypeptide translation product with a Mr of 77,000 when MOD-1 mRNA was used to direct in vitro protein synthesis. Thus, it is possible that MOD-1 malic enzyme mRNA contains an additional polypeptide coding sequence. The translation of such a sequence might disrupt enzyme function and/or markedly decrease enzyme stability. The malic enzyme cDNA probe was also employed to demonstrate that the induction of malic enzyme in the livers of previously starved mice that were fed a high carbohydrate, fat-free diet was controlled pretranslationally by a parallel modulation of the malic enzyme mRNA concentration.
Language of Publication
English
Unique Identifier
84161965

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MeSH Heading (Major)
Cloning, Molecular|*; DNA|*ME; Malate Dehydrogenase|*GE; RNA, Messenger|*AN
MeSH Heading
Animal; Base Sequence; Liver|EN; Mice; Mice, Mutant Strains; Nucleic Acid Hybridization; Support, U.S. Gov't, P.H.S.

Publication Type
JOURNAL ARTICLE
ISSN
0021-9258
Country of Publication
UNITED STATES


Record 98 from database: MEDLINE
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Title
Regulation of hepatic malic enzyme by perfluorodecanoic acid.
Author
Kelling CK; Van Rafelghem MJ; Drake RL; Menahan LA; Peterson RE
Address
School of Pharmacy, University of Wisconsin, Madison 53706.
Source
J Biochem Toxicol, 1986 Sep, 1:3, 23-37
Abstract
Perfluorodecanoic acid (PFDA) administration to adult male rats increased both the activity of hepatic malic enzyme and liver weight in a dose-dependent manner. Hepatomegaly and augmented activity of malic enzyme in liver were apparent within one day following PFDA administration and reached a plateau by three days posttreatment. Malic enzyme quantity per liver in PFDA-treated rats was elevated within one day following dosing and increased continually throughout five days posttreatment. Administration of PFDA to rats in the fed state also led to an increase in the specific activity of hepatic malic enzyme that peaked at three days following dosing. When compared to the fed condition, rats fasted for 48 hours had a decrease in both relative liver weight and the quantity of supernatant protein per liver. The total activity (U/liver) and specific activity of malic enzyme in the liver were also reduced in the fasted state. During the 24 hours after treatment in rats fasted for 48 hours, the body weight as well as the absolute and relative liver weight of animals receiving vehicle declined continuously in the absence of feed. Following the administration of PFDA to fasted rats, body weight was maintained until eight hours posttreatment but then declined at a rate similar to that found with the vehicle-treated group. Absolute and relative liver weight in PFDA-treated rats were increased significantly at eight hours posttreatment when compared to those receiving vehicle, and this increment was maintained throughout the rest of the 24 hours following dosing. While the activity and enzyme content of hepatic malic enzyme decreased in the vehicle-treated group, administration of PFDA to rats fasted for 48 hours prevented their decline. The specific activity of hepatic malic enzyme in 48 hours fasted rats receiving PFDA was also elevated significantly at 16 hours posttreatment. Thus, the administration of PFDA to the adult male rat in both the fed and fasted nutritional states was found to regulate hepatic malic enzyme by not only increasing enzyme quantity but also by augmenting the specific activity, (ie, catalytic state) of the enzyme.
Language of Publication
English
Unique Identifier
90156341

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MeSH Heading (Major)
Decanoic Acids|*PD; Fluorocarbons|*PD; Liver|DE/*EN/ME; Malate Dehydrogenase|*ME
MeSH Heading
Animal; Body Weight|DE; Dose-Response Relationship, Drug; Enzyme Induction|DE; Male; Organ Weight|DE; Rats; Rats, Inbred Strains; Support, U.S. Gov't, Non-P.H.S.; Support, U.S. Gov't, P.H.S.

Publication Type
JOURNAL ARTICLE
ISSN
0887-2082
Country of Publication
UNITED STATES


Record 99 from database: MEDLINE
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Title
AP-1 and T3RE cis elements operate as a functional unit in the transcriptional control of the human malic enzyme gene.
Author
González-Manchón C; Ayuso MS; Parrilla R
Address
Department of Pathophysiology and Human Molecular Genetics, Centro de Investigaciones Biológicas (CSIC), Velázquez 144, 28006, Madrid, Spain.
Source
Gene, 1999 Jan 8, 226:1, 111-9
Abstract
The human malic enzyme (hME) promoter contains an inverted palindromic (IP4) 3,5,3'-triiodo-thyronine (T3) response element (T3RE) 15bp downstream from an activating protein-1 (AP-1) site. The purpose of this study was to analyze the functional relationship between both cis-acting elements. The following observations indicate that these two elements operate as a functional unit in controlling the human ME gene:T3 failed to stimulate transcription above the basal levels in cells overexpressing either TRb or TRb/retinoid acid receptor (RXR), indicating that TRbeta acts primarily as a transcriptional repressor in the context of the hME. Moreover, the finding of a repressive effect of TRbeta without DNA binding suggests the existence of both DNA-dependent and independent mechanisms of TRbeta-induced repression of transcription.
Language of Publication
English
Unique Identifier
99107775

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MeSH Heading (Major)
Malate Dehydrogenase|*GE/ME; Receptors, Thyroid Hormone|DE/GE/*ME; Regulatory Sequences, Nucleic Acid|*; Response Elements|*PH; Transcription Factor AP-1|GE/*ME
MeSH Heading
DNA|ME; DNA-Binding Proteins|GE/ME; Gene Expression Regulation; Human; Mutation; Promoter Regions (Genetics); Receptors, Retinoic Acid|GE/ME; Support, Non-U.S. Gov't; Transcription Factors|GE/ME; Transcription, Genetic; Triiodothyronine|ME/PD

Publication Type
JOURNAL ARTICLE
ISSN
0378-1119
Country of Publication
NETHERLANDS
CAS Registry/EC Number
EC 1.1.1.37 (Malate Dehydrogenase); 0 (retinoid X receptor); 0 (DNA-Binding Proteins); 0 (Receptors, Retinoic Acid); 0 (Receptors, Thyroid Hormone); 0 (Transcription Factor AP-1); 0 (Transcription Factors); 6893-02-3 (Triiodothyronine); 9007-49-2 (DNA)


Record 100 from database: MEDLINE
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Title
Determination of dissociation constants for enzyme-reactant complexes for NAD-malic enzyme by modulation of the thiol inactivation rate.
Author
Kiick DM; Allen BL; Rao JG; Harris BG; Cook PF
Address
Source
Biochemistry, 1984 Nov, 23:23, 5454-9
Abstract
Incubation of NAD-malic enzyme from Ascaris suum with the sulfhydryl reagents N-ethylmaleimide (NEM), 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB), or 4,4'-dithiodipyridine (4-PDS) results in rapid and complete loss of malate oxidative decarboxylase and pyruvate reductive carboxylase activities. With DTNB, this loss of activity occurs concomitantly with the modification of about 1 thiol group per subunit. The majority of the activity is lost when 0.5 thiol per subunit is modified, indicative of possible half-site reactivity with DTNB. Complete restoration of activity follows addition of dithiothreitol to enzyme inactivated by DTNB and 4-PDS but not with NEM. With the DTNB-inactivated enzyme, replacement of the thionitrobenzoate moiety with cyanide restores activity. The presence of a divalent metal ion (Mg2+ or Mn2+) results in enhancement of the inactivation rate with all sulfhydryl reagents. However, malate alone or competitors of malate provide protection which is more effective in the presence of Mg2+, while NAD provides only about 25% protection. Thus, the Ascaris suum NAD-malic enzyme has a thiol group probably located in or near the malate binding site, which is not essential for enzyme activity. The changes in the rate of inactivation in the presence of reactants were used to determine the dissociation constants for enzyme-reactant complexes. These data suggest that all three possible binary and all three possible ternary complexes form. The binding of malate to free enzyme exhibits negative cooperativity, which is eliminated by the presence of either NAD or Mg2+.(ABSTRACT TRUNCATED AT 250 WORDS)
Language of Publication
English
Unique Identifier
85072841

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MeSH Heading (Major)
Ascaris|*EN; Malate Dehydrogenase|*AI/ME; NAD|*ME/PD; Sulfhydryl Compounds|*; Sulfhydryl Reagents|*PD
MeSH Heading
Animal; Dithionitrobenzoic Acid|PD; Ethylmaleimide|PD; Hydrogen-Ion Concentration; Kinetics; Magnesium|PD; Malates|PD; Manganese|PD; Pyridines|PD; Support, U.S. Gov't, P.H.S.

Publication Type
JOURNAL ARTICLE
ISSN
0006-2960
Country of Publication
UNITED STATES
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Dear Karl,                                        

 

 

 

 

SUBSCRIBE:  The Wednesday Letter is a free electronic monthly newsletter written and published by Karl Loren.  You can view more than 50 back issues of this publication by clicking here.  The Wednesday Letter subscription list is maintained on a secure server, no name is ever given or sold to anyone, and it is never used except for this Newsletter.  It is automatically published on the Tuesday night just before the first Wednesday of every month.  You can subscribe to this free monthly electronic letter by entering your eMail address and name below.  You will then automatically receive a request for confirmation, sent to whatever address you have entered.  If you do NOT receive this confirmation request, then you will not be subscribed.  There may have been an error with your address and you should resubmit.  The letter is never sent twice to the same address -- so you do not have to worry about a duplicate subscription.  When you receive this confirmation request you must reply to it, or your subscription will not become active.  No one can subscribe your name, and address, without you being notified, and if you get an unwanted notice of subscription you only need to DO NOTHING and the subscription will NOT be active.

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Personal Message:  When you send a personal message to Karl Loren, you will receive a personal reply as per his instructions.  Karl pledges that every personal message will get a personal answer. When you provide your mail address, we will send you free information including our free catalog and a cassette tape lecture by Karl Loren about heart disease, no charge, by mail, even if outside the US.  You can select particular information you would like to receive, along with the free cassette tape and catalog.

You can reach Vibrant Life in many ways, including by mail to Vibrant Life, 2808 N. Naomi St., Burbank, CA 91504.  Within the US and Canada, use the toll free number:  (800) 523-4521, the local number:  (818) 558-1799, the FAX:  (818) 558-7299, eMail to kimberly@oralchelation.com or any one of the hundreds of message forms throughout the 50 web sites.  Vibrant Life normally ships the same day we get an order.  There are message forms on each of the 100,000+ pages on this and other sites where you can communicate with Vibrant Life.  Check out our companion site, at:  http://www.oralchelation.net where Karl's 2000 page book is published.  Karl Loren is the author and webmaster for this BOOK, as well as for another web site about ORAL CHELATION.  His personal philosophical articles are at PHILOSOPHY

Copyright © May 20, 2008 6:24 AM by Karl Loren on behalf of Vibrant Life, ALL RIGHTS RESERVED.  Permission is granted for non-commercial downloading, copying, distribution or redistribution on two conditions:  One, that some form of copyright notice is included in every copy distributed or copied, showing the copyright belonging to Vibrant Life, Burbank, CA, at www.oralchelation.com . The second condition is that the material is not to be used for any purpose contrary to the purposes and objectives of this site.  This permission does not extend to materials on this site which are copyrighted by others.