Malic Acid
100 Scientific Studies About Malic Acid
Malic
Acid |
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- Search all fields for: malic acid
- Published in 1980 through 1999
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Documents: 1 to 100 of 656
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
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