Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.1.1.37 (malate dehydrogenase)
4,591 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The generalization that 'when a metabolic sequence involves consecutive nicotinamide-adenine dinucleotide-dependent reactions, the dehydrogenases have the same stereospecificity' was tested and confirmed for three metabolic sequences. (1) NAD+-xylitol (D-xylulose) dehydrogenase and NADP+-xylitol (L-xylulose) dehydrogenase are both B-specific. (2) D-Mannitol 1-phosphate dehydrogenase and D-sorbitol 6-phosphate dehydrogenase are both B-specific. (3) meso Tartrate dehydrogenase and oxaloglycollate reductive decarboxylase are both A-specific. Other dehydrogenases associated with the metabolism of meso-tartrate in Pseudomonas putida, such as hydroxypyruvate reductase and tartronate semialdehyde reductase, were also shown to be A-specific. Malate dehydrogenase from Pseudomonas putida was A-specific, and the proposition is discussed that the common A-stereospecificity among the dehydrogenases involved in meso-tartrate metabolism reflects their origin from malate dehydrogenase.
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PMID:The stereospecificity of sequential nicotinamide-adenine dinucleotide-dependent oxidoreductases in relation to the evolution of metabolic sequences. 120 Sep 95

The lipogenic capacity of omental adipose tissue and liver was measured in vitro from samples obtained at slaughter from 33 young male goats. The animals were slaughtered either on the day of weaning (d 0) or 2, 14, or 56 d after weaning. Ages at weaning were 4 wk (early weaning) or 6 or 8 wk (late weaning). Blood samples from the jugular vein were taken before slaughter to measure the concentrations of plasma glucose and nonesterified fatty acids. There was a 30% decrease in glucose concentration after weaning. Nonesterified fatty acid concentration increased fourfold between d 0 and 2 after weaning. By d 14 after weaning, nonesterified fatty acids returned to basal concentration. The lipoprotein lipase (LPL) activity of adipose tissue declined markedly (90%) on d 2 after weaning. Lipoprotein lipase activity returned to preweaning values by d 56 after weaning in those goats that had ad libitum access to feed. In adipose tissue, nicotinamide adenine dinucleotide phosphate (NADP)-malate dehydrogenase activity fell by only 17% by d 2 after weaning and to 63% by d 14 after weaning. Lipoprotein lipase activity was closely related to metabolizable energy intake the day before slaughter. Acetyl-coenzyme A carboxylase activity was low in adipose tissue and it increased only slightly by d 56 after weaning. The data indicated that LPL played a preponderant role in the restoration of lipid stores after weaning. High NADP-malate dehydrogenase activity together with a high concentration of plasma glucose by d 56 after weaning suggested that this enzyme activity could be enhanced by high glucose availability in goat kids. Activities of lipase, acetyl-coenzyme A carboxylase, NADP-malate dehydrogenase, and glucose-6-phosphate dehydrogenase in liver were essentially unaffected by weaning. The extent and rapidity of change of lipogenic enzymes of goat kids was much more pronounced in adipose tissue than in liver.
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PMID:Changes in activities of lipogenic enzymes in adipose tissue and liver of growing goats. 136 29

A model has been built for the plant NADP-malate dehydrogenase from Zea mays, a key enzyme in photosynthesis, which undergoes light-dependent regulation. The model was based on sequence and presumed structural homology to the known three-dimensional structure of mammalian porcine cytosolic NAD-malate dehydrogenase. A cystine-loop present in an extended C-terminal region of plant NADP-malate dehydrogenases was modelled using molecular mechanics and computer graphical methods, based on the assumption that a disulphide bridge exists in the inactive form of the enzyme between Cys351 and Cys363. The predicted conformation of the intact C-terminal cystine-loop suggests that the extended polypeptide will bind in the active centre and inhibit enzyme activity. Another ionizable cysteine residue in the active site is predicted to control the charge of the catalytic His215 and might be responsible for the uniquely tight binding of the positively charged nicotinamide ring of NADP+ in this and other C4 and C3 plant NADP-malate dehydrogenases.
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PMID:A prediction of the three-dimensional structure of maize NADP(+)-dependent malate dehydrogenase which explains aspects of light-dependent regulation unique to plant enzymes. 158 36

Several key enzymes related to carbohydrate metabolism were assayed in Setaria digitata. In the cytosolic fraction pyruvate kinase, phosphoenolpyruvate carboxykinase, malate dehydrogenase, malic enzyme, aspartate transaminase and alanine transaminase were found. Among the TCA cycle enzymes succinate dehydrogenase, fumarate reductase, fumarase (malate dehydration), malate dehydrogenase (malate oxidation and oxaloacetate reduction) and malic enzyme (malate decarboxylation) were detected in the mitochondrial fraction. Only reduced nicotinamide adenine dinucleotide (NADH) dehydrogenase, NADH oxidase and NADH-cytochrome c reductase were found in the mitochondrial fraction. The significance of these results with respect to the metabolic capabilities of the worm are discussed.
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PMID:Intermediary carbohydrate metabolism in the adult filarial worm Setaria digitata. 177 15

The effects of rotenone on the succinate-driven reduction of matrix nicotinamide nucleotides were investigated in Percoll-purified mitochondria from potato (Solanum tuberosum) tubers. Depending on the presence of ADP or ATP, rotenone caused an increase or a decrease in the level of reduction of the matrix nicotinamide nucleotides. The increase in the reduction induced by rotenone in the presence of ADP was linked to the oxidation of the malate resulting from the oxidation of succinate. Depending on the experimental conditions, malic enzyme (at pH 6.6 or in the presence of added CoA) or malate dehydrogenase (at pH 7.9) were involved in this oxidation. At pH 7.9, the oxaloacetate produced progressively inhibited the succinate dehydrogenase. In the presence of ATP the production of oxaloacetate was stopped, and succinate dehydrogenase was protected from inhibition by oxaloacetate. However, previously accumulated oxaloacetate transitorily decreased the level of the reduction of the NAD+ driven by succinate, by causing the reversal of the malate dehydrogenase reaction. Under these conditions (i.e. presence of ATP), rotenone strongly inhibited the reduction of NAD+ by succinate-driven reverse electron flow. No evidence for an active reverse electron transport through a rotenone-insensitive path could be obtained. The inhibitory effect of rotenone was masked if malate had previously accumulated, owing to the malate-oxidizing enzymes which reduced part or all of the matrix NAD+.
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PMID:Succinate-driven reverse electron transport in the respiratory chain of plant mitochondria. The effects of rotenone and adenylates in relation to malate and oxaloacetate metabolism. 200 Dec 41

During operation, biopsies from the gastrocnemius muscle and, in some cases, from the sartorius muscle were taken from 32 patients with peripheral arterial occlusive disease and from 5 subjects with normal peripheral circulation. In patients with inadequate circulation only during exercise, when compared with the control group, increased activities of enzymes involved in oxidative metabolism (malate dehydrogenase, nicotinamide adenine dinucleotide phosphate-dependent isocitrate dehydrogenase, cytochrome C oxidase, creatine kinase), in amino acid metabolism (asparate aminotransferase, alanine aminotransferase), and in anaerobic glycoysis (lactate dehydrogenase) were found. In patients with circulatory disturbances that manifested themselves already at rest, enzyme activities were, with the exception of LDH, lower than those of patients with exclusively exercise-related insufficiency. By means of intraindividual comparisons with the corresponding enzyme activities in the sartorius muscle, the author was able to show that the changes found were not simply the result of differences in training conditions. The diminished concentrations of energy-rich phosphate are an expression of the anaerobic metabolic state in patients with inadequate circulation at rest. It is concluded that chronic ischemia of muscle leads to changes in the energy metabolism of the cell. In the presence of more nearly adequate circulation at rest, the portion of oxidative potential of the total energy metabolism increases. In contrast, if there is an inadequate circulation at rest, the mainly anaerobic glycolysis becomes quantitatively predominant.
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PMID:Investigations on the biochemical characteristics of chronically underperfused muscle. 201 45

Assay conditions were established for the fatty acid elongation and the delta 9 desaturase enzyme systems of bovine liver and adipose tissue microsomes; rat liver microsomes were used as a reference. Overall fatty acid elongation was determined by measuring the incorporation of [2-14C]malonyl-coenzyme A (CoA) to 14C-labeled stearate. Rat liver elongation activity was .50 +/- .02 nmol.min-1.mg protein-1; bovine liver microsomal elongation activity was substantially lower (P less than .05), with a mean value of .15 +/- .02 nmol.min-1.mg protein-1. The elongation activity of bovine s.c. adipose tissue microsomes (.42 +/- .10 nmol.min-1.mg protein-1) was not different (P greater than .05) from the activity observed in rat liver microsomes. To determine the fatty acid delta 9 desaturase activity, microsomes were incubated in the presence of [1-14C]stearoyl-CoA and nicotinamide adenine dinucleotide (reduced form) (NADH), and the production of radioactively labeled oleate was quantified. Microsomal delta 9 desaturase activity was similar in rat liver and bovine s.c. adipose tissue microsomes with rates of .15 +/- .04 and .21 +/- .05 nmol.min-1.mg protein-1, respectively. However, no desaturase activity was detected in bovine liver microsomes, indicating that the liver is not a major site of oleate synthesis in this species. To investigate differences in fatty acid metabolism relative to breed type, eight Angus and seven Braford heifers were slaughtered at approximately 12 mo of age. Subcutaneous fat thickness over the 12th-13th thoracic vertebrae was greater in the Angus heifers than in the Braford heifers. However, no differences (P greater than .05) were observed in mean adipocyte size or number of cells per gram of adipose tissue between the Angus and Braford heifers. Similarly, there were no significant differences between the Angus and Braford s.c. adipose tissues for microsomal fatty acid elongation or delta 9 desaturation, or for nicotinamide adenine dinucleotide phosphate (NADP)-malate dehydrogenase, fatty acid synthetase, or the pentose cycle reductases. The inability of bovine liver to convert stearate to oleate was in agreement with the fatty acid composition of the liver lipid, which had a smaller percentage of oleate and a higher percentage of stearate than s.c. adipose tissue.
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PMID:Fatty acid elongation and desaturation enzyme activities of bovine liver and subcutaneous adipose tissue microsomes. 206 Dec 39

The stereospecificity of the enzyme-dependent oxidation of alpha-[4R-2H]NADH has been determined for four dehydrogenases: two pro-R specific enzymes, pig heart malate dehydrogenase and yeast alcohol dehydrogenase; and two pro-S specific enzymes, rabbit muscle glycerol-3-phosphate dehydrogenase and Rhodopseudomonas spheroides 3-hydroxybutyrate dehydrogenase. In all cases, an enzyme-dependent and substrate-specific oxidation to alpha-NAD+ is observed with the stereochemistry of oxidation identical with that found for the oxidation of the correspondingly labeled beta-NADH. The ability of dehydrogenases from diverse sources to utilize alpha-NADH in a stereochemically competent fashion is discussed in relation to proposed interactions between the nicotinamide sugar moiety and active site residues or obligatory alignments of the pyridine and sugar moieties.
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PMID:The stereospecificity of oxidation of alpha-[4R-2H]NADH by dehydrogenases. 294 36

A single administration of nicotinamide (62.5 mg/kg) was found to enhance the relative activity of exogenous insulin, to decrease glucose level in the peripheral blood, to increase the activity of malate dehydrogenase and glucose-6-phosphate dehydrogenase in the liver cytosol in intact mice and to increase the rate of exogenous glucose utilization in rabbits. The character of nicotinamide effect on carbohydrate metabolism in intact animals is suggested to be dose-dependent. When administered in low doses, the drug increases tissue sensitivity to endo- and exogenous insulin.
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PMID:[Effect of nicotinamide on body glucose utilization in animals]. 297 Mar 99

Three variations to the structure of the nicotinamide adenine dinucleotide (NAD)-dependent L-lactate dehydrogenase from Bacillus stearothermophilus were made to try to change the substrate specificity from lactate to malate: Asp197----Asn, Thr246----Gly, and Gln102----Arg). Each modification shifts the specificity from lactate to malate, although only the last (Gln102----Arg) provides an effective and highly specific catalyst for the new substrate. This synthetic enzyme has a ratio of catalytic rate (kcat) to Michaelis constant (Km) for oxaloacetate of 4.2 x 10(6)M-1 s-1, equal to that of native lactate dehydrogenase for its natural substrate, pyruvate, and a maximum velocity (250 s-1), which is double that reported for a natural malate dehydrogenase from B. stearothermophilus.
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PMID:A specific, highly active malate dehydrogenase by redesign of a lactate dehydrogenase framework. 320 Dec 42


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