Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.4.3.11 (glutamate dehydrogenase)
 4,437 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

NAD- and NADP-dependent dehydrogenases in gastric adenocarcinoma and undifferentiated cancer cells were studied comparatively. The activity of NADP-dependent malate dehydrogenase, glutamate dehydrogenase and glucose-6-phosphate dehydrogenase was found to be high in gastric adenocarcinoma, while there was noted a more high activity of succinate dehydrogenase and NAD-dependent malate dehydrogenase in undifferentiated cancer. Differences ni the activity of oxido-reductive enzymes in adrenocarcinoma and undifferentiated cancer are discussed from the standpoint of various histogenesis of these forms of gastric cancer.
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PMID:[Oxidoreductase activity in the cells of stomach cancer]. 48 98

This communication describes the isolation and characterization of mutants of Rhizobium trifolii which can induce nitrogenase activity in defined liquid medium. Two procedures were used for the isolation of these mutants from R. trifolii strain DT-6: (1) following chemical mutagenesis, slow growing mutants were selected which were unable to utilize NH+4 as sole source of nitrogen; (2) as spontaneous mutants resistant to the glutamate analogue L-methionine-DL-sulfoximine. Mutants (DT-71, DT-125) isolated by these procedures induced nitrogenase activity in the free-living state, whereas the parent strain lacked this property. Induction of nitrogenase activity in these mutants occurred during the late exponential phase of growth when the rate of protein synthesis was decreasing. The addition of NH+4 to a medium containing glutamate as the nitrogen-source resulted in a 50--70% reduction (repression?) of nitrogenase activity; in contrast, the rate of protein synthesis or the rate of respiration was not influenced by exogenous NH+4. Biochemical analysis showed that these mutants (strains DT-71 and DT-125) have defects in both nitrogen and carbon metabolism. The levels of glutamate synthase (both NADP+ -and NAD+ -dependent activities) and glutamate dehydrogenase (NAD+-dependent activity) were markedly lower. In addition, the mutants were found to have no detectable ribitol dehydrogenase or beta-galactosidase activity. These findings are discussed in relation to a mechanism of regulation of symbiotic nitrogen fixation.
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PMID:Regulation of nitrogen fixation in Rhizobium spp. Isolation of mutants of Rhizobium trifolii which induce nitrogenase activity. 58 92

The enthalpy change for the oxidative deamination of glutamate by NADP+ catalyzed by bovine liver glutamate dehydrogenase has been determined calorimetrically. The deltaH0 values are 64.6 +/- 1.2 kJ/mol and 70.3 +/- 1.2 kJ/mol at 25 and 35 degrees C respectively. The equilibrium constants for the reaction at the two temperatures were determined spectrophotometrically. This enabled the determination of deltaG0 and deltaS0 of the reaction as well. deltaH0 values were also determined for the reaction using an alternative coenzyme and the deuterated substrate.
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PMID:Thermodynamics of the glutamate dehydrogenase catalytic reaction. 62 77

The mode of inhibition of NADP-dependent glutamate dehydrogenase by adenylic nucleoside phosphates (ATP, ADP, AMP) was studied with Saccharomyces vini. AMP was found to be a competitive inhibitor for glutamate dehydrogenase whereas the action of ADP and ATP was of a mixed character.
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PMID:[Nature of wine yeast glutamate dehydrogenase inhibition by adenylic nucleoside phosphates]. 70 52

The subcellular distribution of mitochondrial enzymes was studied in cerebral hemispheres of 15-day-old and adult rats. At both ages the synaptosomal fraction contained very little glutamate dehydrogenase (EC 1.4.1.2) but significant amounts of succinate dehydrogenase (EC 1.3.99.1), glutaminase (EC 3.5.1.2), hexokinase (EC 2.7.1.1), malate NADP dehydrogenase (EC 1.1.1.40) and beta-hydroxybutyrate dehydrogenase (EC 1.1.1.30). In immature brain, in the fraction enriched with free (perikaryal) mitochondria, the concentrations of these enzymes were 9.5, 1.8, 2.0, 0.92, 1.5, and 2.1 times higher, respectively, than in the synaptosomes. The increase with age in succinate dehydrogenase and glutaminase was restricted to free mitochondria while hexokinase and malate NADP dehydrogenase accumulated and beta-hydroxybutyrate dehydrogenase diminished in both fractions. In adult brain, too, where the above ratios became 7.5, 5.2, 3.5, 0.84, 1.4, and 2.0, respectively, the concentrations of enzymes relative to each other distinguished clearly between free and synaptic mitochondria. The results substantiate previously noted signs of mitochondrial heteroeneity in adult brain, and extend them to immature brain. The chemical composition, the quantitative pattern of enzymes, of free and synaptic mitochondria is clearly different, and undergoes separate changes during postnatal differentiation.
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PMID:Distribution of mitochondrial enzymes between the perikaryal and synaptic fractions of immature and adult rat brain. 83 6

The occurrence and levels of activity of various enzymes of carbohydrate catabolism in culture forms (promastigotes) of 4 human species of Leishmania (L. brasiliensis, L. donovani, L. mexicana, and L. tropica) were compared. These organisms possess enzymes of the Embden-Meyerhof pathway but lack lactate dehydrogenase. No evidence could be found for the production of lactic acid by growing cultures and lactic acid could not be detected either in cell-free preparations or after incubation of cell-free extracts with pyruvate and NADH under appropriate conditions. All 4 species possess alpha-glycerophosphate dehydrogenase and alpha-glycerophosphate phosphatase which together could regenerate NAD, thus compensating for the absence of lactate dehydrogenase. The oxidative and nonoxidative reactions of the hexose monophosphate pathway are present in all 4 species. Cell-free extracts have pyruvate dehydrogenase activity which allows the entry of pyruvate into and its subsequent oxidation through the tricarboxylic acid cycle. All enzymes of this cycle, including a thiamine pyrophosphate dependent alpha-ketoglutarate dehydrogenase, are present. Both NAD and NADP-linked malate dehydrogenase activities are present. The isocitrate dehydrogenase is NADP specific. There is an active glutamate dehydrogenase which could compete with alpha-ketoglutarate dehydrogenase for the common substrate (alpha-ketoglutarate). Replenishment of C4 acids is accomplished by heterotrophic CO2 fixation catalyzed by pyruvate carboxylase. All 4 species have high levels of NADH oxidase activity. Several enzymes thus far not found in any species of Leishmania have been demonstrated. These are: phosphoglucose isomerase, triose phosphate isomerase, fructose-1, 6-diphosphatase, 3-phosphoglycerate kinase, enolase, alpha-glycerophosphate dehydrogenase, alpha-glycerophosphate phosphatase, pyruvate dehydrogenase complex, citrate synthase, aconitase, alpha-ketoglutarate dehydrogenase, glutamate dehydrogenase, and NADH oxidase.
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PMID:Enzymes of carbohydrate metabolism in four human species of Leishmania: a comparative survey. 100 46

Genetic manipulation of nitrogenase and key glutamate-forming enzymes can provide mutants that excrete fixed N2 as NH4+. A derepressed N2 fxation mutant (SK-24) has been isolated , which excretes up to 20.2 mumol of fixed N2 as NH4+ per mg of cell protein in 24 hr at room temperature. Biochemical analysis shows that this mutant, which requires glutamate for growth, releases fixed N2 as NH4+ into the environment because of (i) constitutive synthesis of nitrogenase and (ii) genetic blocks resulting in losses of glutamate synthase [L-glutamine:2-oxoglutarate aminotransferase (NADPH oxidizing), EC 2.6.1.53] and glutamate dehydrogenase [L-glutamate:NADP oxidoreductase (deaminating), EC 1.4.1.4] activities, enzymes essential for NH4+ assimilation into cell material. The parent strain (asm-1), missing only glutamate synthase activity, also actively excretes NH4+ during early phases of its growth but eventually reutilizes the NN4+. A miximum yield of 4.0 mumol of NH4+/ml per 24 hr has been noted for asm-1 only during the growth period. Biosynthesis of NH4+ PROCEEDS AT THE EXPENSE OF A Variety of fermentable sugars, such as sucrose or glucose, with a maximum energy conversion efficiency of about 5 glucose degraded per NH4+ formed. The use of microbes for production of NH4+ fertilizer is discussed.
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PMID:Microbial production of ammonium ion from nitrogen. 109 Sep 30

Mutants, designated tamAr, have been isolated on the basis of simultaneous resistance to toxic analogues thiourea, aspartate hydroxamate and chlorate with L-alanine as the sole nitrogen source. tamAr mutants are also resistant to methylammonium. This resistance of tamAr mutants is correlated with partially repressed activity of a number of enzyme and transport systems regulated by ammonium. Furthermore, tam-Ar mutants have low NADP-glutamate dehydrogenase (NADP-GDH) activity and also efflux ammonium under certain growth conditions. Mutants at the areA locus (areAr) have also been isolated on the basis of resistance to these analogues, with nitrate or L-aspartate as the nitrogen source. These, similar to tamAr lesions, result in resistance to methylammonium and are partially repressed for ammonium repressible system, but in contrast to tamAr, areAr alleles have wild-type NADP-GDH activity and normal ammonium efflux. tamAr and areAr mutants grow as wild type on all nitrogen or carbon sources tested, are recessive, and appear to be epistatic to all other mutations (gdhA1, meaA8 and meaB6) which result in derepressed levels of ammonium regulated system. Whereas tamAr and areAr phenotypes are additive, tamAr is epistatic to areAd phenotype.
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PMID:Studies of partially repressed mutants at the tamA and areA loci in Aspergillus nidulans. 110 54

When malic enzyme is added to a mixture of malate-2-d, TPN, CO2, pyruvate, and TPNH at concentrations calculated to be at equilibrium, the TPNH level first drops and then increases slowly to its original level. This equilibrium perturbation is caused by slower cleavage of C-D than C-H bonds during hydride transfer as malate-2-d and TPNH are partly converted into TPND and malate-2-h in the process of establishing isotopic equilibrium. With malate-2-d, isotope effects for malic enzyme at pH 7.1 and malate dehydrogenase at pH 9.3 of 1.45 and 1.70-2.16 (depending on oxaloacetate level) were determined with this method, while the corresponding isotope effects on V/Kmalate and V for the chemical reactions were 1.5-1.8 and 1.0, and 1.9 and 1.5 for the two enzymes. The advantage of this method is its extreme sensitivity, and the lack of interference from various artifacts. The sensitivity is sufficient to permit determination of 13C and 15N isotope effects in favorable cases, and values of 1.031 for malic enzyme with 13CO2, and 1.047 for glutamate dehydrogenase with 15NH4+ have been determined. In the course of this work it was discovered that the equilibrium constants for oxidation by DPN, and oxidative decarboxylation by TPN are lower for malate-2-d than for malate-2-h by a factor of 0.76-0.82. Changes in Keq upon deuterium substitution, which are predicted by the calculations of Hartshorn and Shiner (1972), should be observed for many other reactions as well.
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PMID:Equilibrium perturbation by isotope substitution. 119 42

Four strains of Desulfovibrio each excreted pyruvate to a constant level during growth; it was re-absorbed when the substrate (lactate) was exhausted. Malate, succinate, fumarate and malonate also accumulated during growth. One of the strains (Hildenborough) excreted alpha-ketoglutarate as well as pyruvate when incubated in nitrogen-free medium; the former was re-absorbed on addition of NH4Cl. In a low-lactate nitrogen-free medium, strain Hildenborough rapidly re-absorbed the pyruvate initially excreted, but did not re-absorb the alpha-ketoglutarate. Arsenite (I mM) prevented the accumulation of alpha-ketoglutarate; I mM-malonate did not affect the accumulation of keto acids. Isocitrate dehydrogenase activity (NAD-specific) in all strains was lower than NADP-specific glutamate dehydrogenase activity. Alpha-Ketoglutarate dehydrogenase could not be detected in any strain. NADPH oxidase activity was demonstrated. This and previous work indicate that a tricarboxylic acid pathway from citrate to alpha-ketoglutarate exists in Desulfovibrio spp., and that succinate can be synthesized via malate and fumarate; however, an intact tricarboxylic acid cycle is evidently not present. The findings are compared with observations on biosynthetic pathways in clostridia, obligate lithotrophs, phototrophs, and methylotrophs, and various facultative bacteria.
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PMID:Keto acid metabolism in Desulfovibrio. 119 93


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