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)

Suspensions in water of two species of Fusobacterium leaked several coenzymes when incubated at normal growth temperatures. Chromatography of filtrates from these suspensions revealed the presence of NAD, NADP, FMN, tetrahydrofolic acid and, in one of the two, pyridoxal phosphate. Analyses of some enzymic activities in whole organisms demonstrated deficiencies in coenzymes:glutamate dehydrogenase was virtually inactive in the absence of added NAD; tryptophanase activities were diminished by washing but the extent differed between strains; histidase activity was not decreased by washing or suspension in water or saline. Both lag phase and doubling time increased markedly in severely washed organisms inoculated into fresh medium. Addition of appropriate coenzymes shortened the lag phase for both strains and shortened the doubling time in one.
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PMID:The effect of coenzyme leakage and replacement on the growth and metabolism of two fusobacteria. 23 3

The enzymes involved in the assimilation of ammonia by free-living cultures of Rhizobium spp. are glutamine synthetase (EC. 6.o.I.2), glutamate synthase (L-glutamine:2-oxoglutarate amino transferase) and glutamate dehydrogenase (ED I.4.I.4). Under conditions of ammonia or nitrate limitation in a chemostat the assimilation of ammonia by cultures of R. leguminosarum, R. trifolii and R. japonicum proceeded via glutamine synthetase and glutamate synthase. Under glucose limitation and with an excess of inorganic nitrogen, ammonia was assimilated via glutamate dehydrogenase, neither glutamine synthetase nor glutamate synthase activities being detected in extracts. The coenzyme specificity of glutamate synthase varied according to species, being linked to NADP for the fast-growing R. leguminosarum, R. melitoti, R. phaseoli and R. trifolii but to NAD for the slow-growing R. japonicum and R. lupini. Glutamine synthetase, glutamate synthase and glutamate dehydrogenase activities were assayed in sonicated bacteroid preparations and in the nodule supernatants of Glycine max, Vicia faba, Pisum sativum, Lupinus luteus, Medicago sativa, Phaseolus coccineus and P. vulgaris nodules. All bacteroid preparations, except those from M. sativa and P. coccineus, contained glutamate synthase but substantial activities were found only in Glycine max and Lupinus luteus. The glutamine synthetase activities of bacteroids were low, although high activities were found in all the nodule supernatants. Glutamate dehydrogenase activity was present in all bacteroid samples examined. There was no evidence for the operation of the glutamine synthetase/glutamate synthase system in ammonia assimilation in root nodules, suggesting that ammonia produced by nitrogen fixation in the bacteroid is assimilated by enzymes of the plant system.
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PMID:Ammonia assimilation by rhizobium cultures and bacteroids. 23 5

Methods are described in which liberation of ammonia from amino acid substrates by the D- and L-amino acid oxidases may be coupled with the NADH-dependent reductive amination of 2-oxoglutarate catalysed by exogenous glutamate dehydrogenase (L-glutamate: NAD oxidoreductase (deaminating), EC 1.4.1.2). The inhibition of D-amino acid oxidase (D-amino acid:O2 oxidoreductase (deaminating), EC 1.4.3.3) by ADP needed to activate and stabilise glutamate dehydrogenase was relieved by FAD, and the substrate was D-alanine at approximately 6-fold Km concentration. Neither FAD or FMN were required in the L-amino acid oxidase (L-amino acid:O2 oxidoreductase (deaminating), EC 1.4.3.2) assay; this utilised L-leucine as substrate in a concentration approximately 7-fold the Km value. The methods were reasonably sensitive and precise, and a linear relationship between activity and enzyme concentration prevailed up to an absorbance change of 0.050 per min. They have the advantage of being amenable to automation and to employment of fluorescence techniques should greater sensitivity be required.
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PMID:Coupled optical rate determinations of amino acid oxidase activity. 23 96

Glutamate dehydrogenase have been obtained in crystalline form from purified ox liver nuclear fractions. The enzyme appeared homogeneous, as judged by several electrophoretic techniques at two pH values. A comparative study with the widely known ox liver mitochondrial glutamate dehydrogenase revealed several common features, such as the allosteric effect of the nucleotides ADP and GTP, the activation at high concentrations of the cofactor NAD+, and the existence of a concentration-dependent reversible monomer-polymer(s) equilibrium. However, the two enzymes differed in many other respects. Inorganic phosphate activated nuclear glutamate dehydrogenase to a much greater extent than the mitochondrial enzyme; the substrate NH4+ showed cooperative homotropic interactions only with nuclear glutamate dehydrogenase; kinetic differences were detected with most of the reaction substrates, as well as different rates of oxidative deamination of other L-amino acids, the nuclear enzyme had a higher anodic mobility and a different chromatographic behavior on anionic exchangers. The latter evidence indicates that the glutamate dehydrogenase activity in liver is associated with two proteins which are structurally different, thus confirming the results of a separate immunological study. Preliminary evidence suggests that the enzyme in nuclei is attached to the nuclear envelope, probably the inner membrane, from which it can be solubilized by the addition of salts.
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PMID:Crystallization and partial characterization of glutamate dehydrogenase from ox liver nuclei. 24 85

Use of the gel film technique in microphotometric determinations of enzyme activity is described. The microscope photometer is computer-controlled. It is programmed to deal with repetitive measurements at up to 12 selected positions within a tissue section and to evaluate recorded reaction rates statistically. Films of polyacrylamide gel with entrapped glucose-6-phosphate dehydrogenase are used as a model to demonstrate the correlation between local enzyme activity and the microphotometrically determined reaction rate. Enzyme activities at different positions in the same tissue section are determined and compared. Activity profiles of five enzymes (glutamate dehydrogenase, lactate dehydrogenase, malate dehydrogenase, succinate dehydrogenase, NAD-dependent tetrazolium reductase) in the liver are presented and show non-uniform intra-acinar distribution patterns. These results are interpreted in the light of the metabolic zonation of the hepatic acinus. Further applications of the method are discussed.
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PMID:Microphotometric determination of enzyme activities in cryostat sections by the gel film technique. 26 70

A simple, rapid (2 hours), fluorescent test for the activity of blood adenosine deaminase (ADA) is described. The test which can be performed on both heparinized and dried blood, is based on the conversion of adenosine to inosine and ammonium in the presence of ADA. The enzyme activity is visually estimated by the oxidation of NADH (fluorescent) to NAD+ (non-fluorescent) in a coupled reaction with glutamate dehydrogenase. The disappearance of fluorescence indicates ADA activity in the sample. The advantages are discussed of the use of this test for the study of the autosomal recessive severe combined immunodeficiency.
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PMID:A simple rapid fluorescent assay for adenosine deaminase activity. 31 78

Biotin deficiency resulted in an increased growth rate of Aspergillus nidulans. The activities of hexokinase and aldolase were not much changed during the growth cycle, but activities of glucose-6-phosphate dehydrogenase and NADP-linked glutamate dehydrogenase increased significantly during the exponential phase. This change was remarkable during biotin deficiency. In contrast to the higher growth rate and respiration rate during biotin deficiency the activities of NAD(P)H oxidoreductases were low. An inverse relationship between the activity of tyrosinase and melanin content was observed. A role of the DOPA-DOPA-quinone system in maintaining culture growth is suggested.
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PMID:Growth, glucose metabolism and melanin formation in biotin-deficient Aspergillus nidulans. 40 7

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

In a detailed study focused on the methodological problems in dehydrogenase histochemistry [e.g., fixation, diffusion of enzymes and of reduced inermediates, conversion of NADPH and NADP to NADH and NAD, respectively, penetration of tetrazolium salt and formazan substantivity, 'nothing dehydrogenase' reaction, use of exogenous CoQ10 and of flavoprotein substitute (PMS)], the distribution and activity of succinate dehydrogenase, NAD(P)H-tetrazolium reductase, glucose-6-phosphate dehydrogenase, lactate dehydrogenase (H and M types), and of L-glutamate dehydrogenase (E.C.1.4.1.2 and E.C.1.4.1.3) have been investigated in the rat cerebellum. It was evident from the study that reliable results could only be obtained if all the aforementioned factors had been considered. The image of actual concentration of SDH in the neuropil of the molecular layer could only be recorded by adding CoQ10, while other structures exhibited greater balance between SDH and endogenous mitochondrial CoQ. Contrary to previous studies, a reversed localization of the activity of G-6-PDH and LDH was noticed. The elements of molecular and Purkinje layers were rich in G-6-PDH, while the granular layer was nearly depleted. The actual level of LDH could only be recorded if NADH-tetrazolium reductase was bypassed with PMS. The H and M types of LDH coexisted in the three cortical layers, the H type being prevalent and the M type attaining its highest level in synaptic glomeruli followed by the structures of the molecular layer and the Purkinje cells. High activity of GDH was noticed in Bergmann glia followed by synaptic glomeruli, while most other structures showed weak to moderate activity. The two GDH types coexisted in all structures showing activity, except for Bergmann cells, which only showed presence of the E.C. 1.4.1.3 type. Furthermore, Bergmann glia was exceptional by showing no activity of SDH and LDH, but strong activity of G-6-PDH and NADPH-tetrazolium reductase. The granular cells were exceptional by showing weak or no activity of all enzymes in question.
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PMID:Methodological aspects of the histochemical localization and activity of some cerebellar dehydrogenases. 66 87


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