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)

Yeast mutant lacking proteinase B activity have been isolated [Wolf, D. H. and Ehmann, C. (1978) FEBS Lett. 92, 121--124]. One of these mutants (HP232) is characterized in detail. Absence of the vacuolar localized enzyme is confirmed by checking for proteinase B activity in isolated mutant vacuoles. Defective proteinase B activity segregates 2:2 in meiotic tetrads. The mutation is shown to be recessive. Mutant proteinase B activity is not only absent against the synthetic substrate. Azocoll, but also against the physiological substrate pre-chitin synthetase, cytoplasmic malate dehydrogenase and fructose-1,6-bisphosphatase. The mutant shows normal vegetative growth, a phenomenon not consistent with the idea that proteinase B might be the activating principle of chitin synthetase zymogen in vivo. Fluorescence microscopy shows normal chitin insertion. Enzymes underlying carbon-catabolite inactivation in wild-type cells (a mechanism proposed to be possibly triggered by proteinase B) such as cytoplasmic malate dehydrogenase, fructose-1,6-bisphosphatase, phosphoenolpyruvate carboxykinase and isocitrate lyase, are inactivated also in the mutant. NADP-dependent glutamate dehydrogenase, which is found to be inactivated in glucose-starved wild-type cells, proceeds normally in the mutant. Mutant cells show more than 40% reduced protein degradation under starvation conditions. Sporulating diploids, homozygous for proteinase B absence, also exhibit an approximately 40% reduced protein degradation as compared to homozygous wild-type diploids or diploids heterozygous for the mutant gene. The time of the appearance of the first ascospores of diploid cells, homozygous for proteinase B deficiency, is delayed about 50% and sporulation frequency is reduced to about the same extent as compared to homozygous wild-type diploids or diploids heterozygous for the mutant gene.
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PMID:Studies on a proteinase B mutant of yeast. 38 14

Enzymes of parasite origin were identified by starch-gel electrophoresis. The species of parasite studied were Plasmodium berghei, Plasmodium yoelii nigeriensis, Babesia rodhaini and Anthemosoma garnhami. Lactate dehydrogenase, glucose phosphate isomerase and (NADP) glutamate dehydrogenase were detected in all species; phosphogluconate dehydrogenase was detected in both Plasmodium species but malate dehydrogenase only in P. y. nigeriensis. Glucose-6-phosphate dehydrogenase, alanine aminotransferase and aspartate aminotransferase were not detected in any parasite.
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PMID:Biochemistry of intraerythrocytic parasites. I. Identification of enzymes of parasite origin by starch-gel electrophoresis. 38 67

1. The cultured, epimastigote-form of Trypanosoma cruzi contains NADP-linked glutamate dehydrogenase (EC 1.4.1.4), with a molecular weight of about 280,000, similar to the enzyme from Plasmodium chabaudi and different from the enzymes from higher animal sources. 2. T. cruzi also contains aspartate aminotransferase (EC 2.6.1.1), with properties similar to those of the enzyme from mammals. 3. The concerted action of the transaminase and glutamate dehydrogenase might be responsible for the production of NH3 which characterizes the protein catabolism in T. cruzi.
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PMID:Glutamate dehydrogenase and aspartate aminotransferase in Trypanosoma cruzi. 40 Sep 47

1. The NADP-linked glutamate dehydrogenase purified from epimastigotes of Trypanosoma cruzi was strongly, but not completely, inhibited by sulfhydryl reagents, in the presence of Tris-HCl or phosphate buffers. 2. The enzyme modified by preincubation with o-iodosobenzoate had a kinetic behaviour different from that shown by the enzyme modified with other inhibitors, such as N-ethylmaleimide or p-chloromercuribenzoate. 3. The inhibition by o-iodosobenzoate was additive with the inhibition by the other reagents tested. 4. It is suggested that two or more different sulfhydryl groups, placed probably near the active site, are involved in these effects.
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PMID:Inhibition of the NADP-linked glutamate dehydrogenase from Trypanosoma cruzi by sulfhydryl reagents. 40 Sep 63

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

Stopped-flow studies of the initial burst of NADPH production accompanying the oxidative deamination of L-glutamate by L-glutamate dehydrogenase and NADP+ were performed in the presence of alpha-ketoglutarate, a product of the reaction. Both binary enzyme-alpha-ketoglutarate and ternary enzyme--NADP+-alpha-ketoglutarate complexes are inhibitory in the burst presence of the enzyme-catalyzed reaction. Order-of-addition experiments show the binary complex to form rapidly, in the 3 ms dead time of the stopped-flow instrument. There is a distinct lag, however, in the achievement of the full ternary complex inhibitory effect unless the enzyme is preincubated with both NADP+ and alpha-ketoglutarate prior to initiation of the catalytic reaction with L-glutamate. The formation of an inhibitory enzyme--NADP+-alpha-ketoglutarate complex appears to be sufficiently slow to give a delayed kinetic response when alpha-ketoglutarate is added to the reaction system.
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PMID:Transient-state kinetics of L-glutamate dehydrogenase: mechanism of alpha-ketoglutarate inhibition in the burst phase. 56 27

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

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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