Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.4.1.2 (glutamate dehydrogenase)
 4,380 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The activities of citrate synthase and NAD+-linked and NADP+-linked isocitrate dehydrogenases were measured in nervous tissue from different animals in an attempt to provide more information about the citric acid cycle in this tissue. In higher animals the activities of citrate synthase are greater than the sum of activities of the isocitrate dehydrogenases, whereas they are similar in nervous tissues from the lower animals. This suggests that in higher animals the isocitrate dehydrogenase reaction is far-removed from equilibrium. If it is assumed that isocitrate dehydrogenase activities provide an indication of the maximum flux through the citric acid cycle, the maximum glycolytic capacity in nervous tissue is considerably greater than that of the cycle. This suggest that glycolysis can provide energy in excess of the aerobic capacity of the tissue. 2. The activities of glutamate dehydrogenase are high in most nervous tissues and the activities of aspartate aminotransferase are high in all nervous tissue investigated. However, the activities of alanine aminotransferase are low in all tissues except the ganglia of the waterbug and cockroach. In these insect tissues, anaerobic glycolysis may result in the formation of alanine rather than lactate.
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PMID:Activities of citrate synthase, NAD+-linked and NADP+-linked isocitrate dehydrogenases, glutamate dehydrogenase, aspartate aminotransferase and alanine aminotransferase in nervous tissues from vertebrates and invertebrates. 0 Oct 3

In the nerve tissue with proliferating macroglia cells were observed a lowered oxygen consumption, an increased aerobic glycolysis and alanine formation and a higher alanine aminotransferase and glutamate dehydrogenase activity than in the control tissue in the homogenates and in the cell sap fraction. The substrate saturation curves, apparent Km and pH optimum values in the tissue with proliferating macroglia and in the control did not differ from one another. The authors assume that a higher alanine aminotransferase activity in the tissue with macroglia proliferation can reflect either a higher synthesis of the enzyme in the altered tissue, or a predominance of glial elements in the altered tissue possessing a higher alanine aminotransferase activity than the nerve cells.
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PMID:Alanine formation and alanine aminotransferase activity in the nerve tissue with proliferating macroglia. 0 40

We have isolated mutant strains (nit) of Salmonella typhimurium that are defective in nitrogen metabolism. They have a reduced ability to use a variety of compounds including glutamate, proline, arginine, N-acetyl-glucosamine, alanine, and adenosine as sole nitrogen source. In addition, although they grow normally on high concentrations of ammonium chloride (greater than 1 mM) as nitrogen source, they grow substantially more slowly than wild type at low concentrations (less than 1 mM). We postulated that the inability of these strains to utilize low concentrations of ammonium chloride accounts for their poor growth on other nitrogen sources. The specific biochemical lesion in strains with a nit mutation is not known; however, mutant strains have no detectable alteration in the activities of glutamine synthetase, glutamate synthetase, or glutamate dehydrogenase, the enzymes known to be involved in assimilation of ammonia. A nit mutation is suppressed by second-site mutations in the structural gene for glutamine synthetase (glnA) that decrease glutamine synthetase activity.
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PMID:Mutant strains (nit) of Salmonella typhimurium with a pleiotropic defect in nitrogen metabolism. 1 Feb 75

The photosynthetic bacterium Rhodopseudomonas capsulata lacks glutamate dehydrogenase and normally uses the glutamine synthetase/glutamate synthase sequence of reactions for assimilation of N2 and ammonia. The glutamine synthetase in cell-free extracts of the organism is completely sedimented by centrifugation at 140,000 X g for 2 h, is inhibited by L-alanine but not by adenosine 5'-monophosphate, and exhibits two apparent Km values for ammonia (ca. 13 muM and 1 mM).
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PMID:Inorganic nitrogen assimilation by the photosynthetic bacterium Rhodopseudomonas capsulata. 1 Feb 81

The nicotinamide adenine dinucleotide phosphate-dependent glutamate dehydrogenase (NADP-GDH) from the food yeast Candida utilis was found to be rapidly inactivated when cultures were starved of a carbon source. The addition of glutamate or alanine to the starvation medium stimulated the rate of inactivation. Loss of enzyme activity was irreversible since the reappearance of enzyme activity, following the addition of glucose to carbon-starved cultures, was blocked by cycloheximide. A specific rabbit antibody was prepared against the NADP-GDH from C. utilis and used to quantitate the enzyme during inactivation promoted by carbon starvation. The amount of precipitable antigenic material paralleled the rapid decrease of enzyme activity observed after transition of cells from NH(4) (+)-glucose to glutamate medium. No additional small-molecular-weight protein was precipitated by the antibody as a result of the inactivation, suggesting that the enzyme is considerably altered during the primary steps of the inactivation process. Analysis by immunoprecipitation of the reappearance of enzyme activity after enzyme inactivation showed that increase of NADP-GDH activity was almost totally due to de novo synthesis, ruling out the possibility that enzyme activity modulation is achieved by reversible covalent modification. Enzyme degradation was also measured during steady-state growth and other changes in nitrogen and carbon status of the culture media. In all instances so far estimated, the enzyme was found to be very stable and not normally subject to high rates of degradation. Therefore, the possibility that inactivation was caused by a change in the ratio of synthesis to degradation can be excluded.
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PMID:Evidence for the degradation of nicotinamide adenine dinucleotide phosphate-dependent glutamate dehydrogenase of Candida utilis during rapid enzyme inactivation. 2 41

To determine whether Salmonella typhimurium has a nitrogen control response, we have examined the regulation of nitrogen utilization in two mutants with fivefold and threefold elevations in their glutamine synthetase activities. The mutants do not require glutamine for growth on glucose--ammonia medium but do have altered growth on other nitrogen sources. They grow better than an isogenic control on media containing arginine or asparate, but more slowly with proline or alanine as nitrogen sources. This unusual growth pattern is not due to altered regulation of the ammonia assimilatory enzymes, glutamate dehydrogenase and glutamate synthase, or to changes in the enzymes for aspartate degradation. However, transport for several amino acids may be affected. Measurement of amino acid uptake show that the mutants with high glutamine synthetase levels have increased rates for glutamine, arginine, aspartate, and lysine, but a decreased rate for proline. The relationship between glutamine synthetase levels and uptake was examined in two mutants with reduced, rather than increased, glutamine synthetase production. The uptake rates for glutamine and lysine were lower in these two glutamine auxotrophs than in the Gln+ controls. These results show a correlation between the glutamine synthetase levels and the uptake rates for several amino acids. In addition, the pleiotropic growth of the mutants with elevated glutamine synthetase activities suggests that a nitrogen control response exists for S. typhimurium and that it can be altered by mutations affecting glutamine synthetase regulation.
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PMID:Salmonella typhimurium LT-2 mutants with altered glutamine synthetase levels and amino acid uptake activities. 3 Jul 54

Rhodopseudomonas acidophila strain 7050 assimilated ammonia via a constitutive glutamine synthetase/glutamate synthase enzyme system. Glutamine synthetase had a Km for NH+4 of 0.38 mM whilst the nicotinamide adenine dinucleotide linked glutamate synthase had a Km for glutamine of 0.55 mM. R. acidophila utilized only a limited range of amino acids as sole nitrogen sources: L-alanine, glutamine and asparagine. The bacterium did not grow on glutamate as sole nitrogen source and lacked glutamate dehydrogenase. When R. acidophila was grown on L-alanine as the sole nitrogen source in the absence of N2 low levels of a nicotinamide adenine dinucleotide linked L-alanine dehydrogenase were produced. It is concluded, therefore, that this reaction was not a significant route of ammonia assimilation in this bacterium except when glutamine synthetase was inhibited by methionine sulphoximine. In L-alanine grown cells the presence of an active alanine-glyoxylate aminotransferase and, on occasions, low levels of an alanine-oxaloacetate aminotransferase were detected. Alanine-2-oxo-glutarate aminotransferase could not be demonstrated in this bacterium.
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PMID:Nitrogen assimilation in Rhodopseudomonas acidophila. 3 Nov 45

The urea cycle enzymes, carbamoyl-P-synthetase, ornithine transcarbamylase, arginase and other enzymes related to ammonia metabolism, such as glutamate dehydrogenase, glutamine synthetase and alanine and aspartate aminotransferases,have been studied in thioacetamide-induced liver disease in rats. Urea and ammonia were determined both in serum and in liver extracts. Glutamate and aspartate were determined in liver extracts. There was a marked decrease (in brackets: fraction of control) in carbamoyl-P-synthetase (0.23), ornithine transcarbamylase (0.36) and arginase (0.62). The accumulation of ammonia (3.22) and the decreased urea level (0.80) are well known indications of liver failure. Glutamate dehydrogenase and glutamine synthetase increased respectively to 1.50 and 1.33, and the changes in glutamate and aspartate levels were respectively 1.68 and 0.92; this indicates that the metabolic route: 2-oxoglutarate leads to glutamate leads to glutamine is increased, and thereby compensates for the low rate of urea formation. Aminotransferase activities were respectively 0.43 and 0.25. No significant differences were found in serum aminotransferases, or in the concentrations of ammonia and urea.
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PMID:The effect of thioacetamide on urea cycle enzymes of rat liver. 3 82

Chronic ammonia toxicity in experimental mice was induced by exposing them for 2 and 5 days to 5 % (v/v) ammonia solution. The enzymes concerned with glutamate metabolism (aspartate-, alanine- and tyrosine aminotransferases, glutamate dehydrogenase and glutamine synthetase) and (Na+ + K+)-ATPase were estimated in the three regions of brain (cerebellum, cerebral cortex and brain stem) and in liver. Glutamate, aspartate, alanine, glutamine and GABA, RNA and protein were also estimated in the three regions of brain and liver. A significant rise in the activity of (Na+ + K+)-ATPase in all the three regions of brain along with a fall in the activity of alanine aminotransferase was noticed. Changes in the activities of other enzymes were also observed. A significant increase in alanine and a decrease in glutamic acid was observed while no change was observed in the content of other amino acids belonging to the glutamate family. As a result of this, changes in the ratios of glutamate/glutamine and glutamate + aspartate/GABA was observed. The results indicated that the brain was in a state of more depression and less of excitation. Under these conditions the liver tissue was showing a profound rise in the activity of the enzymes of glutamate metabolism. The results are further discussed.
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PMID:Chronic metabolic effects of ammonia in mouse brain. 9 19

Alanine and glutamine formation and release were studied using the intact epitrochlaris preparation of rat skeletal muscle. Alanine release from skeletal muscle was increased by fasting (65%), cortisone (145%), thyroxine (200%), and diabetes (185%). Glutamine release was decreased by cortisone (37%) and diabetes (23%) but not significantly affected by fasting or thyroxine. Tissue levels of alanine were unchanged but tissue glutamine levels were markedly reduced (30 to 60%) in all treatment groups. Insulin added in vitro did not affect amino acid release even with preparations obtained from diabetic animals. Inhibition of glycolysis with 0.2 mM iodoacetate had no effect on the rate of alanine and glutamine formation in any treatment group. Pyruvate generation was increased by all treatments even in the presence of the inhibitor. Total skeletal muscle alanine, aspartate, and branched chain aminotransferase, glutamate dehydrogenase, and malic enzyme activities were not significantly altered in any treatment groups. The addition of 10 mM aspartate, cysteine, branched chain amino acids, and serine significantly increased alanine formation, whereas the maximal rate of glutamine formation in the presence of stimulating amino acids was reduced in each treatment groups--the most marked effects were noted with cortisone and diabetic preparations. Although accelerated muscle proteolysis is an important factor regulating alanine formation in skeletal muscle, the redirection of carbon flow from glutamine toward alanine formation observed in fasting, cortisone, thyroxine-treated, and diabetic rats, indicates that factors other than proteolysis also participate in the control of amino acid release from muscle.
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PMID:Alanine and glutamine synthesis and release from skeletal muscle. III. Dietary and hormonal regulation. 12 73


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