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)

1. In order to assess whether the potential ability of heart ventricular muscle and liver to metabolise substrates such as alanine, aspartate and lactate varies as the sheep matures and its nutrition changes, the activities of the following enzymes were determined in tissues of lambs obtained at varying intervals between 50 days after conception to 16 weeks after birth and in livers from adult pregnant ewes: lactate dehydrogenase (EC 1.1.1.27), alanine aminotransferase (EC 2.6.1.2), pyruvate kinase (EC 2.7.1.40), pyruvate carboxylase (EC 6.4.1.1), phosphoenolpyruvate carboxykinase (GTP)(EC 4.1.1.32), malate dehydrogenase (EC 1.1.1.37), aspartate aminotransferase (EC 2.6.1.1) and citrate (si)-synthase (EC 4.1.3.7). 2. In the heart a most marked increase in alanine aminotransferase activity was found throughout development. During this period the activities of citrate (si)-synthase, lactate dehydrogenase and pyruvate carboxylase also increased. There were no substantial changes in the activities of aspartate aminotransferase, malate dehydrogenase or pyruvate kinase. Pyruvate kinase activities were five times greater in the heart compared with those found in the liver. No significant activity of phosphoenolpyruvate carboxykinase (GTP) was detected in heart muscle. 3. In the liver the activities of both alanine aminotransferase and aspartate aminotransferase increased immediately following birth although the activity of alanine aminotransferase was lower in livers of pregnant ewes than in any of the lambs. As with alanine aminotransferase the highest activities of lactate dehydrogenase were found during the period of postnatal growth. No marked changes were observed in malate dehydrogenase or citrate (si)-synthase activities during development. A small decline in pyruvate kinase activity occurred whilst the activities of pyruvate carboxylase and phosphoenolpyruvate carboxykinase (GTP) tended to rise during development.
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PMID:Activities of enzymes concerned with pyruvate and oxaloacetate metabolism in the heart and liver of developing sheep. 117 28

In order to assess the functional state of the liver in 45 repair service workers of a chemical plant producing pesticides the serum concentration and electrophoretic pattern of proteins, the concentration of bilirubin and the activity of alkaline phosphatase, gamma-glutamyl- transpeptidase, alanine and aspartate aminotransferase, and lactic and malic dehydrogenase were determined. As compared to 35 healthy controls, not exposed to noxious chemicals, a significantly lower serum protein concentration with higher percentage of gamma-globulins and lower albumins and alpha 2-globulins were observed, the serum alanine and aspartate aminotransferase activities were significantly elevated. Ultrasound examination of the hepatic structure revealed liver steatosis in 11 (24.4%) workers. The results of our study point to a discrete lesion of the liver.
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PMID:[Biochemical indices of liver function in workers from repair brigades in chemical plants "Organika-Azot" in Jaworz]. 128 52

Isolated hepatocytes from hypothyroid, euthyroid and hyperthyroid rats have been employed to investigate the relative importance of reducing-equivalent shuttles for the transfer of hydrogen between cytoplasm and mitochondria during simultaneous ureogenesis and gluconeogenesis. In cells from hypothyroid animals, a 58% depression of glucose formation and 68% reduction in ureogenesis were induced by n-butylmalonate, an inhibitor of the malate shuttle. A more reduced state of the cytoplasmic compartment and a substantial fall in the concentrations of pyruvate, aspartate, alanine and glutamate accompanied this inhibition. Preincubation of cells with n-butylmalonate yielded greater inhibitory effects than observed in the absence of preincubation. The inhibitory effects on gluconeogenesis and ureogenesis were less in cells from euthyroid rats and were very much reduced in the case of glucose synthesis and absent in the case of ureogenesis, in cells from hyperthyroid rats. It is inferred that both the malate-aspartate and alpha-glycerophosphate shuttles may function in the transfer of reducing equivalents from cytoplasm to mitochondria during ureogenesis in hepatocytes. The major inhibition by n-butylmalonate of glucose and urea synthesis in hepatocytes from hypothyroid rats is due to the diminished activity of the alpha-glycerophosphate shuttle in these cells. Moreover, it follows that the NADH arising from the cytoplasmic malate dehydrogenase-catalysed reaction is accessible to both the malate-aspartate shuttle and the alpha-glycerophosphate shuttle.
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PMID:Reducing-equivalent transfer to the mitochondria during gluconeogenesis and ureogenesis in hepatocytes from rats of different thyroid status. 135 45

Metabolism of glucose and L-amino acids in an obligately aerobic marine bacterium isolated from Pacific mackerel intestines was investigated for the mechanism and pathway of eicosapentaenoic acid (EPA) biosynthesis. This bacterium could not uptake glucose but the cell-free extract of this bacterium had the enzymatic activities of L-alanine oxidase (EC 1.4.3.2), L-alanine dehydrogenase (EC 1.4.1.1). L-serine dehydratase (EC 4.2.1.13), and malate dehydrogenase (EC 1.1.1.40), and of seven enzymes involved in the TCA cycle of the usual aerobes. On the other hand, the carbon-13 concentration in cellular fatty acids of the bacterium, especially that in their methyl carbon atoms in contrast to their carbonyl carbons, increased drastically when the bacterium was grown in the presence of 13CH3COONa. These results indicate that: (i) the TCA cycle works in this bacterium, (ii) glucose is not utilized and pyruvic acid is in vivo synthesized from L-alanine, L-serine, and malic acid, and (iii) EPA and other cellular fatty acids are in vivo synthesized from acetyl coenzyme A by the usual de novo synthesis route.
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PMID:Metabolism of L-amino acids in a marine bacterium isolated from mackerel intestines in relation to eicosapentaenoic acid biosynthesis. 136 63

The examination of model robustness in the previous paper (Shiraishi, F., and Savageau, M. A. (1992) J. Biol. Chem. 267, 22919-22925 led to the suggestion that the current model for the tricarboxylic acid cycle in Dictyostelium discoideum is ill-determined with respect to one or more of the features reflecting pyruvate metabolism. This conclusion is further supported here by results of steady state and dynamic analyses. The tricarboxylic acid cycle, according to the current model, is poised on a knife's edge with its behavior rigidly determined; any alteration of the system's components leads to nonviable behavior, as exemplified by explosive accumulation of pyruvate and loss of steady state in response to a minute change in the level of malate dehydrogenase. With the additional results in this paper, we are able to refine the diagnosis of the problem and suggest three different areas of the current model that might profitably be re-examined by experiment. These include the kinetics of the reactions at the malate branch point, the turnover times for the alanine, glutamate, and aspartate pools in vivo, and the dynamic mass balances for the cofactor NAD. We also suggest a minimal modification in the current model that could alleviate or circumvent some of these problems.
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PMID:The tricarboxylic acid cycle in Dictyostelium discoideum. III. Analysis of steady state and dynamic behavior. 142 43

The effect of acute and subacute doses of L-methionine-DL-sulfoximine (MSI) were studied on the activities of pyruvate dehydrogenase, enzymes of citric acid cycle and aspartate and alanine aminotransferases in the mitochondria, synaptosomes and cytosol of rat brain. In general, the activities of pyruvate dehydrogenase and of the citric acid cycle enzymes, except malate dehydrogenase (malate----oxaloacetate), were elevated in all 3 subcellular fractions. Malate dehydrogenase activity (malate----oxaloacetate) was suppressed in the mitochondria while the activity of this enzyme in the reverse direction was enhanced in the cytosol. Activities of aspartate and alanine aminotransferases were suppressed under these conditions. As the effects of MSI on these enzymes were similar to those observed upon the administration of ammonium salts, it is suggested that the hyperammonemic state induced by MSI might derange the operation of the malate-aspartate shuttle. Increased activities of citric acid cycle enzymes in the cytosol suggested the existence of a small population of mitochondria which was highly vulnerable either to ammonia or to MSI.
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PMID:Effect of methionine sulfoximine on pyruvate dehydrogenase, citric acid cycle enzymes and aminotransferases in the subcellular fractions isolated from rat cerebral cortex. 230 51

Activity levels of pyruvate dehydrogenase, enzymes of citric acid cycle, aspartate and alanine aminotransferases were estimated in mitochondria, synaptosomes and cytosol isolated from brains of normal rats and those injected with acute and subacute doses of ammonium acetate. In mitochondria isolated from animals treated with acute dose of ammonium acetate, there was an elevation in the activities of pyruvate, isocitrate and succinate dehydrogenases while the activities of malate dehydrogenase (malate----oxaloacetate), aspartate and alanine aminotransferases were suppressed. In subacute conditions a similar profile of change was noticed excepting that there was an elevation in the activity of alpha-ketoglutarate dehydrogenase in mitochondria. In the synaptosomes isolated from animals administered with acute dose of ammonium acetate, there was an increase in the activities of pyruvate, isocitrate, alpha-ketoglutarate and succinate dehydrogenases while the changes in the activities of malate dehydrogenase, aspartate and alanine amino transferases were suppressed. In the subacute toxicity similar changes were observed in this fraction except that the activity of malate dehydrogenase (oxaloacetate----malate) was enhanced. In the cytosol, pyruvate dehydrogenase and other enzymes of citric acid cycle except malate dehydrogenase were enhanced in both acute and subacute ammonia toxicity though their activities are lesser than that of mitochondria. In this fraction malate dehydrogenase (oxaloacetate----malate) was enhanced while activities of malate dehydrogenase (malate----oxaloacetate), aspartate and alanine aminotransferases were suppressed in both the conditions. Based on these results it is concluded that the decreased activities of malate dehydrogenase (malate----oxaloacetate) in mitochondria and of aspartate aminotransferase in mitochondria and cytosol may be responsible for the disruption of malate-aspartate shuttle in hyperammonemic state.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Activities of pyruvate dehydrogenase, enzymes of citric acid cycle, and aminotransferases in the subcellular fractions of cerebral cortex in normal and hyperammonemic rats. 272 22

A second thioredoxin, distinct from the one reported by Meng and Hogenkamp in 1981 (J. Biol. Chem. 256, 9174-9182), has been purified to homogeneity from an Escherichia coli strain containing a plasmid encoding a Corynebacterium nephridii thioredoxin. Thioredoxin genes from C. nephridii were cloned into the plasmid pUC13 and transformants were identified by complementation of a thioredoxin negative (trxA-) E. coli strain. The abilities of the transformants to support the growth of several phages suggested that more than one thioredoxin had been expressed [Lim et al. (1987) J. Biol. Chem. 262, 12114-12119]. In this paper we present the purification and characterization of one of these thioredoxins. The new thioredoxin from C. nephridii, designated thioredoxin C-2, is a heat-stable protein containing three cysteine residues/molecule. It serves as a substrate for C. nephridii thioredoxin reductase and E. coli and Lactobacillus leichmannii ribonucleotide reductases. Thioredoxin C-2 catalyzes the reduction of insulin disulfides by dithiothreitol or by NADPH and thioredoxin reductase and is a hydrogen donor for the methionine sulfoxide reductase of E. coli. Spinach malate dehydrogenase (NADP+) and phosphoribulokinase are activated by this thioredoxin while glyceraldehyde-3-phosphate dehydrogenase (NADP+) is not. Like the thioredoxin first isolated from C. nephridii, this new thioredoxin is not a reducing substrate for the C. nephridii ribonucleotide reductase. The complete primary sequence of this second thioredoxin has been determined. The amino acid sequence shows a high degree of similarity with other thioredoxins. Surprisingly, in contrast to the other sequences, this new thioredoxin contains the tetrapeptide -Cys-Ala-Pro-Cys- at the active site. With the exception of the T4 thioredoxin, this is the first example of a thioredoxin that does not have the sequence -Cys-Gly-Pro-Cys-. Our results suggest that, like plant cells, bacterial cells may utilize more than one thioredoxin.
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PMID:Purification, characterization and revised amino acid sequence of a second thioredoxin from Corynebacterium nephridii. 291 72

Malate dehydrogenase (EC 1.1.1.37) was purified to homogeneity from the marine diatom Nitzschia alba. The purification steps consisted of (NH4)2SO4 precipitation, ion-exchange chromatography, Blue Sepharose affinity chromatography and gel filtration. A typical procedure provided 685-fold purification with 58% yield. The Mr of the holoenzyme was estimated to be 322,000 by gel filtration and 316,000 by ultracentrifugation. The enzyme migrated as a single polypeptide spot on two-dimensional polyacrylamide-gel electrophoresis with an Mr of 38,500, suggesting that the holoenzyme consists of eight identical subunits. This is the first case where malate dehydrogenase has been shown to be a homo-octamer; malate dehydrogenases from other sources are predominantly homodimers, with two homotetramers reported so far. The amino acid composition of the enzyme was determined and the N-terminal sequence of the subunit polypeptide was found to be Arg-Lys-Val-Ala-Val-Met-Gly-Ala-Ala-Gly-Gly-Ile-Gly-Gln-Pro-Leu-Ser-Leu- Leu-Leu - Lys-Leu-Ser-Pro-Gln-Val-Thr-Glu-Leu-Ser-Lys-Tyr-. For the first 21 amino acid residues, near-identical sequences were reported for the enzymes isolated from pig heart, Escherichia coli, yeast and watermelon. Other physicochemical and catalytic properties, such as sedimentation coefficient, partial specific volume, Stokes radius, excitation and emission maxima, Michaelis constants, pH optima, pH stability range and activation energy, of this enzyme are also presented.
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PMID:Purification and molecular properties of malate dehydrogenase from the marine diatom Nitzschia alba. 293 May 9

This work was performed to gain more information on the role of pyruvate kinase isoenzymes in the regulation of renal carbohydrate metabolism. Immunohistochemically, pyruvate kinase type L is shown to be localized in the proximal tubule of the nephron and pyruvate kinase type M2 in the distal tubule and the collecting duct. a tight relationship between gluconeogenesis and pyruvate recycling was found. The rate of gluconeogenesis (8 mumol/g wet wt. per 30 min) was of the same order of magnitude as the rate of pyruvate recycling (10.92 mumol/g wet wt. per 30 min). Stimulation of gluconeogenesis from 20 mM lactate in kidney cortex slices of 24-h-starved rats by dibutyryl-cAMP, alanine and parathyroid hormone was connected with a decrease in pyruvate recycling; inhibition of gluconeogenesis due to a lack of Ca2+ in the incubation medium was linked with an increase in pyruvate recycling. The degradation of [6-14C]glucose to lactate, pyruvate, ketone bodies and CO2 and of [2-14C]lactate was unaffected by dibutyryl-cAMP, alanine, epinephrine, vasopressin or the omission of Ca2+ from the incubation medium. 1 mM dibutyryl-cAMP or 5 mM alanine did not alter the activities of oxaloacetate decarboxylase, 'malic' enzyme and malate dehydrogenase from rat kidney cortex. Since aerobic glycolysis in the distal tubules and the collecting ducts is not influenced by hormones, dibutyryl-cAMP and Ca2+, pyruvate kinase type M2 residing in this tissue is unlikely to be a control point of glycolysis. Since this tissue degrades only one-seventh of the glucose formed via gluconeogenesis, it does not contribute significantly to pyruvate recycling. Therefore, the decrease of pyruvate recycling in the presence of dibutyryl-cAMP and alanine in rat kidney cortex slices, leading to increased renal gluconeogenesis, has to be ascribed to the regulation of pyruvate kinase type L.
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PMID:Localization and role of pyruvate kinase isoenzymes in the regulation of carbohydrate metabolism and pyruvate recycling in rat kidney cortex. 300 99


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