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 effect of a chronic intake of dietary alcohol upon myocardial enzymes was studied in rats. Alcohol, comprising more than 40% of the dietary calorie content, was administered to rats for 6 or 12 weeks. To assess the metabolic changes in the myocardium, the following enzymes were measured: lactate dehydrogenase (LDH), malate dehydrogenase (MDH), aldolase (ALD), isocitrate dehydrogenase (ICDH), creatine kinase (CK) and glutamate-pyruvate transaminase (GPT). The activity of CK was decreased (4.79 +/- 0.99 U X mg-1 protein) after 6 weeks on alcohol and was significantly different from that of the controls (5.98 +/- 1.44 U X mg-1 protein). After 12 weeks the CK activity of alcoholic rats had recovered to 5.99 +/- 1.08 U X mg protein-1 and approached the value found in the normal myocardium. A pronounced decrease was found in the activity of MDH: 8.26 +/- 0.69 U X mg protein-1 in the controls, and 6.78 +/- 1.07 U X mg protein-1 and 5.79 +/- 0.85 U X mg protein-1 in the alcoholic rats after 6 and 12 weeks, respectively. The LDH activity decreased to a lesser extent, but significantly: 2.45 +/- 0.18 U X mg protein-1 in the controls, and 2.11 +/- 0.07 U X mg protein-1 and 2.06 +/- 0.29 U X mg protein-1 after 6 and 12 weeks on test. Only slight, not significant, changes were observed for the other enzymes investigated (ICDH, ALD, GPT).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Enzyme activity changes in rat heart after chronic alcohol ingestion. 668 85

Activity of aspartate aminotransferase, an enzyme which catalyzes the interconversion of the excitatory transmitter candidates, glutamate and aspartate, has been measured in fiber tracts of rat, with an emphasis on sensory and motor systems of the brain. Most tracts had significantly higher activities than the cholinergic facial nerve root, consistent with the possibility that a component of aspartate aminotransferase activity might serve as a marker for neurons using glutamate and/or aspartate as neurotransmitter. Highest activity was in the auditory nerve root. On the other hand, a close correlation was found between aspartate aminotransferase and malate dehydrogenase activities in the fiber tracts, raising the question whether aspartate aminotransferase activity may be more closely related to energy metabolism than to transmitter metabolism.
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PMID:Aspartate aminotransferase activity in fiber tracts of the rat brain. 670 44

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

Propionate inhibits oxygen consumption by rat liver mitochondria when glutamate, alpha-ketaglutarate, and succinate are substrates. Carnitine prevents this effect. The pattern of inhibition of 14CO2 release from metabolic intermediates indicates citric acid cycle inhibition between succinate:coenzyme A (CoA) ligase (GDP) and malate dehydrogenase. Propionyl CoA is synthesized from propionate in mitochondria. Propionyl CoA is a potent inhibitor of succinate:CoA ligase with positive cooperativity and half half-maximal inhibition at 2 X 10(-4) M propionyl CoA.
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PMID:Propionate inhibition of succinate:CoA ligase (GDP) and the citric acid cycle in mitochondria. 678 Sep 67

The distribution of some oxidoreductases were investigated in the regio postcentralis of young, adult and senescent mice brains by means of semiquantitative histoenzymatic methods. It was possible to observe a different spread of activities of 1-malate: NAD oxidoreductase (EC 1.1.1.37) and D-glucose-6-phosphate: NADP oxidoreductase (EC 1.1.1.49) in several layers of the regio postcentralis between young and old animals. The enzyme products of 1-glutamate:NAD(P) oxidoreductase (EC 1.4.1.3), 1-alpha-glycerine-3-phosphate:NAD oxidoreductase (EC 1.1.1.8) and D-glucose-6-phosphate:NADP oxidoreductase (EC 1.1.1.49) in the whole area show a decrease after the 20th month of the life, but it exists strain differences. The investigated enzymes of citric acid cycle were not vary in the ageing process.
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PMID:[Histochemical demonstration of enzyme activity changes in the regio postcentralis of the mouse brain under the effect of the aging process]. 679 20

After prolonged application of ethanol the liver and brain of rats show an appreciable increase in lactate dehydrogenase activity, noticeable lowering of cytoplasmic aspartate and alanine aminotransferase activity, elevation of liver arginine succinate lyase activity with unchanged activities of other enzymes of the ornithine cycle (ornithine carbamoyltransferase and arginase), reduction of glutamate and malate dehydrogenase and mitochondrial aspartate aminotransferase activity in brain tissue. Concurrent application of ethanol and pyridoxine normalizes the effect of ethanol on liver arginine succinate lyase and on brain tissue lactate and malate dehydrogenase, mitochondrial and cytoplasmic aspartate aminotransferase and alanine aminotransferase.
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PMID:[Enzyme activity changes in chronic alcoholic intoxication and the simultaneous administration of pyridoxine]. 689 33

The first enzymatic method involving enzmatic cycling for the assay of a synthetic steroid, medroxyprogesterone acetate (MPA), in plasma is reported. First the steroid is extracted and chromatographically purified, and then it is desacetylated and rechromatographed on the same Lipidex column. The primary enzymatic reaction is carried out with 3 alpha, 20 beta-hydroxy-steroid dehydrogenase and the nicotinamide adenine dinucleotide+ product formed is enzymatically cycled with alcohol dehydrogenase and malate dehydrogenase. Malate, the product formed, is measured in a third enzymatic step with malate dehydrogenase in a medium of glutamate oxaloacetic transaminase. The reduced nicotinamide is measured fluorometrically. The final fluorometric assay's sensitivity is 25-30 fmol. Using 250-mcliter samples, the assay can detect MPA at a level of .6-1 nmol per liter of plasma.
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PMID:Enzymatic assay of medroxyprogesterone acetate in plasma. 699 91

The reverse reaction of aspartate transcarbamylase in which phosphate or arsenate is first coupled to carbamyl aspartate, followed by elimination of aspartate, has been studied under conditions in which one product, aspartate, is removed. Aspartate is converted to oxalacetate by glutamate-oxalacetate transaminase, and the resulting oxalacetate is converted to malate by the NADH, NAD+ oxidoreductase enzyme malate dehydrogenase. Phosphate and carbamyl aspartate saturation curves are nonsigmoidal. The transition state analogue, N-phosphonacetyl-L-aspartate, activates this reverse reaction substantially. Reverse kinetic parameters of the Haldane type are characteristic of the T-state and correlated with the parameters of the usual forward reaction of the T-state. Phosphate and carbamyl aspartate do not alter the thiol reactivity or sedimentation coefficient of the enzyme. These five results indicate that, under the conditions of these experiments, the reverse reaction does not cause the allosteric transition. In a new assay for the forward reaction we couple phosphate production with NADP reduction using phosphorylase a, phosphoglucomutase, and glucose-6-phosphate dehydrogenase.
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PMID:Kinetics of aspartate transcarbamylase from Escherichia coli for the reverse direction of reaction. 702 33

The activity of serum enzymes, such as, creatine kinase (CK), pyruvate kinase (PK), aldolase (ALD), lactate dehydrogenase (LDH), sorbitol dehydrogenase (SbDH), malate dehydrogenase (MDH), glutamate-aspartate aminotransferase (AST), glutamate-alanine aminotransferase (ALT), myokinase (MK), glucosephosphate isomerase (GPI), alkaline phosphatase (AlkP), pseudocholinesterase (PsCHE) isocitrate dehydrogenase and gamma-glutamyltranspeptidase (gamma-GTP), was determined in 256 patients with progressing myodystrophy (PMD) (Duchenne's form in 125, Becker's form in 14, pelvicohumeral form in 36, humeroscapulofacial form in 19, ocular form in 10, other rare forms in 34, and nonidentified forms in 13 patients). In the control group (64 men, 56 women and 50 children), the activity of the enzymes was found to depend on the patients' sex and age. With regard to both parameters, i. e. the degree of the enzyme activity rise and the frequency of the pathological values the most informative were CK, then PK and ALD, and then all the other enzymes. Of all the PMD forms the enzymatic activity appeared to be the highest in patients with the pseudohypertrophic malignant form. By determining the activity of five enzymes (CK, ALD, LDH, AST and ALT) and taking into consideration the patient's age, the onset and the duration of the disease one can distinguish between sick and healthy subjects, as well as between various forms of PMD.
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PMID:[Serum enzyme dynamics in progressive muscular dystrophies]. 703 17

Mitochondrial aspartate transamination was investigated as a major source of oxalacetate for citrate synthesis in rat ventral prostate. Citrate accumulation was measured in isolated mitochondria incubated with acetyl coenzyme A and various combinations of amino acids. Aspartate plus alpha ketoglutarate in the presence of acetyl coenzyme A resulted in significant citrate accumulation. Neither aspartate nor alpha ketoglutarate alone resulted in any significant citrate accumulation. Aspartate and alpha ketoglutarate use was comparable to glutamate and citrate production. The results indicated the presence of a mitochondrial aspartate aminotransferase. Castration (3 days) caused a significant decrease in citrate production from aspartate plus alpha ketoglutarate as well as a decrease in mitochondrial AAT activity in prostate although no effect on kidney activity occurred. A single injection of 1 mg. testosterone propionate to castrate rats significantly increased prostate mitochondrial AAT activity within 24 hours while MDH activity was unaltered. A double reciprocal plot indicated that testosterone might regulate the level of mitochondrial AAT in prostate. Ventral prostate also contain a uniquely high level of endogenous aspartate. These studies indicate that aspartate might be the major 4-carbon source of oxalacetate for citrate synthesis. Also testosterone possibly regulated prostate citrate production by its effect on the level of mitochondrial AAT activity.
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PMID:Mitochondrial aspartate aminotransferase and the effect of testosterone on citrate production in rat ventral prostate. 706 60


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