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. The l-malate dehydrogenase of Pseudomonas ovalis Chester, which is independent of nicotinamide nucleotides and which is structurally and functionally bound to the cell-wall membrane, has been prepared in a soluble form and partially purified. 2. The purified dehydrogenase exhibits a triple cofactor requirement for FAD, quinone and phospholipid, and in the presence of these cofactors can utilize 2,6-dichlorophenol-indophenol as hydrogen acceptor. 3. The formation of reduced forms of FAD was not detected, but in the presence of both FAD and phospholipid the enzyme catalysed the reduction of quinone by l-malate at rates equivalent to those obtained with 2,6-dichlorophenol-indophenol as terminal acceptor. The l-malate dehydrogenase of Ps. ovalis Chester is therefore an l-malate-quinone oxidoreductase. 4. The quinone and the phospholipids present in the fragments of the cell-wall membrane from which the soluble dehydrogenase was prepared have been extracted and purified. The quinone was identified as coenzyme Q(9). At least eight phospholipids were detected, and the major component is an unsaturated phosphatidylethanolamine. 5. The nature of the phospholipid required to activate the enzyme depends on the nature of the quinone used in the assay system. When 2-methyl-1,4-naphthaquinone is used, a wide variety of phospholipids, including all those isolated from the organism, will activate the enzyme, but when coenzyme Q(9) is used the phospholipid specificity of the enzyme is much more restricted, and the most effective activator is the unsaturated phosphatidylethanolamine isolated from the organism. 6. Evidence is presented to support the view that the restricted phospholipid specificity exhibited by the enzyme in the presence of coenzyme Q(9), as opposed to the broad specificity exhibited when 2-methyl-1,4-naphthaquinone is used, is due to the fact that coenzyme Q(9) has a large substituent on position 3.
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PMID:Cofactor requirements of the L-malate dehydrogenase of Pseudomonas ovalis Chester. 596 84

The assimilation and metabolism of CO(2) and acetate by Beggiatoa alba strain B18LD was investigated. Although B. alba was shown to require CO(2) for growth, the addition of excess CO(2) (as NaHCO(3)) to the medium in a closed system did not stimulate growth. Approximately 24 to 31% of the methyl-labeled acetate and 38 to 46% of the carboxyl-labeled acetate were oxidized to (14)CO(2) by B. alba. The apparent V(max) values for combined assimilation and oxidation of [2-(14)C]acetate by B. alba were 126 to 202 nmol min(-1) mg of protein(-1) under differing growth conditions. The V(max) values for CO(2) assimilation by heterotrophic and mixotrophic cells were 106 and 131 pmol min(-1) mg of protein(-1), respectively. The low V(max) values for CO(2) assimilation, coupled with the high V(max) values for acetate oxidation, suggested that the required CO(2) was endogenously produced from acetate. Moreover, exogenously supplied acetate was required by B. alba for the fixation of CO(2). From 61 to 73% of the [(14)C]acetate assimilated by washed trichomes was incorporated into lipid. Fifty-five percent of the assimilated [2-(14)C]acetate was incorporated into poly-beta-hydroxybutyric acid. This was consistent with chemical data showing that 56% of the heterotrophic cell dry weight was poly-beta-hydroxybutyric acid. Succinate and CO(2) were incorporated into cell wall material, proteins, lipids, nucleic acids, and amino and organic acids, but not into poly-beta-hydroxybutyric acid. Glutamate and succinate were the major stable products after short-term [1-(14)C]acetate assimilation. Glutamate and aspartate were the first stable (14)CO(2) fixation products, whereas glutamate, a phosphorylated compound, succinate, and aspartate were the major stable (14)CO(2) fixation products over a 30-min period. The CO(2) fixation enzymes isocitrate dehydrogenase (nicotinamide adenine dinucleotide phosphate; reversed) and malate dehydrogenase (nicotinamide adenine dinucleotide phosphate; decarboxylating) were found in cell-free extracts of both mixotrophically grown and heterotrophically grown cells. The data indicate that the typical autotrophic CO(2) fixation mechanisms are absent from B. alba B18LD and that the CO(2) and acetate metabolism pathways are probably linked.
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PMID:Heterotrophic carbon metabolism by Beggiatoa alba. 611 47

Parietal cells in the luminal segments of mouse gastric glands show high activity of acid-secreting potassium-dependent adenosine triphosphatase (H+, K+-ATPase) and of nicotinamide adenine dinucleotide-linked isocitrate dehydrogenase (NAD-ICDHase) and malate dehydrogenase (MDHase) but low activity of succinate dehydrogenase (SDHase). This pattern of activity is reversed in the basal segments of the same glands. These results and previous morphological findings support the conclusion that luminal segment parietal cells are much more active in hydrochloric acid secretion than those of the basal segment. The origin of this zonation may be either cellular deterioration with age or some more specific form of regulation of parietal cell metabolism.
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PMID:Cytochemical evidence for functional zonation of parietal cells within the gastric glands of the mouse. 631 15

In an effort to assess the effects of phase-state changes on protein conformations, we have compared several properties of cytoplasmic malate dehydrogenase in the crystalline and solution states. Two crystalline forms of the enzyme have been examined: one crystallized in the presence of nicotinamide adenine dinucleotide and the other in its absence. Though both forms catalyze cytoplasmic malate dehydrogenase's normal substrate conversions, they have specific activities 150-3000-fold less than the solution-state enzyme. These dramatic activity decreases cannot be accounted for by diffusion constraints imposed by the crystal lattice nor do they result from the manipulations necessary to crystallize or cross-link the enzyme. Further, crystal- and solution-state enzymes have different pH dependences of their enzymatic activities, have different sensitivities toward inactivation by the covalent inhibitor iodoacetate, and respond differently to nicotinamide adenine dinucleotide protection against this inactivation. Finally, crystals of the enzyme grown in the presence and absence of cofactor are also distinguishable from one another by using the same criteria. Taken together, these results suggest that crystallization perturbs the dynamics and, perhaps, the average conformation of cytoplasmic malate dehydrogenase.
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PMID:Crystallization-induced modification of cytoplasmic malate dehydrogenase structure and function. 666 35

Gossypol, a phenolic compound isolated from the cotton plant, is a powerful inhibitor of nicotinamide adenine dinucleotide-linked enzymes (alpha-hydroxyacid dehydrogenase and malate dehydrogenase) of Trypanosoma cruzi, the parasite that causes Chagas' disease. Parasites at the epimastigote stage that were incubated for 5 minutes with 100 micromolar gossypol were completely immobilized. Concentrations of gossypol as low as 0.01 micromolar markedly reduced the growth rate of T. cruzi in culture.
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PMID:Inhibitory action of gossypol on enzymes and growth of Trypanosoma cruzi. 675 Jul 91

14C-labeled bicarbonate was incorporated into trichloroacetic acid-insoluble material by cell suspensions of A. viscosus strain M100 and also into the four-carbon fermentation product, succinate, but not into the three-carbon fermentation product, lactate. The initial step in the conversion of 14C-labeled bicarbonate into both trichloroacetic acid-insoluble material and succinate was catalyzed by the enzyme phosphoenolypyruvate carboxylase, which served to convert the glycolytic intermediate, phosphoenolpyruvate, and bicarbonate to the four-carbon compound, oxalacetate. The metabolic fate of oxalacetate was its conversion to either trichloroacetic acid-insoluble material or succinate. One pathway by which oxalacetate may be metabolized into acid-insoluble material is via its conversion to the biosynthetic precursor aspartate by the action of glutamate aspartate aminotransferase. One source of the alpha-amino group of aspartate was the ammonium ion, which could be incorporated into glutamate, the substrate of the glutamate aspartate aminotransferase reaction, by the action of a reduced nicotinamide adenine dinucleotide phosphate-dependent glutamate dehydrogenase whose reducing equivalents could be derived from the nicotinamide adenine dinucleotide phosphate-dependent oxidative reactions of the hexose monophosphate pathway catalyzed by glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. Alternatively, oxalacetate was converted to the fermentation product, succinate, through the sequential action of malate dehydrogenase, fumarase, and succinic dehydrogenase. The resolution and partial purification of phosphoenolpyruvate carboxylase, glutamate aspartate aminotransferase, glutamate dehydrogenase, malate dehydrogenase, fumarase, and succinic dehydrogenase are also reported.
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PMID:Carbon dioxide metabolism by Actinomyces viscosus: pathways for succinate and aspartate production. 676 22

This study has investigated the feasibility of calculating the cytoplasmic free [NADP+]/[NADPH] ratio in rat brain. The time course of the change in the substrate ratios of the malate dehydrogenase (decarboxylating) [E.C. 1.1.1.40], NADP+-isocitrate dehydrogenase (decarboxylating) [E.C. 1.1.1.42] and 6-phosphogluconate dehydrogenase (decarboxylating) [E.C. 1.1.1.44] reactions was followed for up to 10 min after a single, unmodified electroconvulsive seizure. From the results it has been concluded that during periods of low flux, the direction and magnitude of the change in the cytoplasmic free [NADP+]/[NADPH] ratio can, in fact, be reasonably determined even though there is some uncertainty in the absolute value of the ratio itself. It is recommended that reliance not be placed on a single enzyme system but that one or both of the other systems also be observed under a given experimental condition to increase confidence in the determination. The results also demonstrate that seizure and anoxia have a far lesser effect on the cytoplasmic free [NADP+]/[NADPH] ratio than on the free [NAD+]/[NADH] ratio in the same compartment. These results suggest that the pathways using the nicotinamide-adenine dinucleotide phosphate system are relatively protected from the rapid fluctuations that seizure and anoxia can produce.
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PMID:The calculation of the cytoplasmic free [NADP+]/[NADPH] ratio in brain: effect of electroconvulsive seizure. 679 9

1. A simple, facile one-step method has been devised to measure the stereospecificity of NADP+-linked oxidoreductases. The procedure involves coupling the test enzymes to enzymes of known stereospecificity in the presence of deuterated substrates. The regenerated NADP+ in the coupled reactions is analyzed by PMR for its deuterium content at the carbon-4 position of the nicotinamide ring. 2. It is found that malate dehydrogenase (EC 1.1.1.37), lactate dehydrogenase (EC 1.1.1.27) and glycerate dehydrogenase (EC 1.1.1.29) are A-side stereospecific whereas glutamate dehydrogenase (EC 1.4.1.3) and glycerol-3-phosphate dehydrogenase (EC 1.1.1.8) are B-side stereospecific. 3. Enzymes which can utilize both NAD+ and NADP+ have the same stereospecificity with respect to the coenzyme.
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PMID:A one-step PMR determination of hydrogen transfer stereospecificity of NADP+-linked oxidoreductases. 682 14

The effect of the increasing the energy content of the diet by supplementation with increasing amounts of carbohydrate on hepatic lipogenesis and the activities of associated enzymes of liver was examined in force-fed growing chicks. Hepatic lipogenesis and the activities of nicotinamide adenine dinucleotide phosphate (NADP-MDH)-malate dehydrogenase (EC 1.1.1.40) and citrate cleavage enzyme (EC 4.1.3.8) in liver were significantly increased as dietary metabolizable energy (ME) increased by supplementation of carbohydrate. Triglyceride content in liver significantly increased as dietary ME increased by supplementation of carbohydrate. The results demonstrated a positive correlation between hepatic fatty acid synthesis and the activities of NADP-malate dehydrogenase and citrate cleavage enzyme in liver.
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PMID:Effect of increasing dietary energy on hepatic lipogenesis in growing chicks. I. Increasing energy by carbohydrate supplementation. 684 8

The effect of increasing the energy content of the diet through supplementation of various levels of fat or protein on hepatic lipogenesis and activities of associated enzymes of liver was examined in force-fed growing chicks. Hepatic lipogenesis was significantly decreased as the dietary metabolizable energy level was increased through supplementation of fat or protein. The activity of nicotinamide adenine dinucleotide phosphate-malate dehydrogenase (NADP-MDH) (EC 1.1.1.40) in liver was higher (P less than .01) in chicks fed diets containing the lowest energy level. The activity of citrate cleavage enzyme (EC 4.1.3.8) in liver was significantly depressed as the dietary metabolizable energy level increased through supplementation of fat, whereas increasing the dietary metabolizable energy level through protein supplementation resulted in a significant increase in citrate cleavage enzyme activity in liver. Nonesterified fatty acid concentration in serum was significantly increased as the dietary metabolizable energy level was increased through supplementation of fat.
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PMID:Effect of increasing dietary energy on hepatic lipogenesis in growing chicks. II. Increasing energy by fat or protein supplementation. 684 9


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