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)

The clearance of glutamate dehydrogenase from plasma was measured weekly for three weeks in three dry and three lactating cows. The clearance was exponential with a mean clearance constant of 0.0488/j and means (+/- SE) half-life of 14.2 (+/- 0.77) h. There were variations among cows and among measurements in the same cow but there was no difference between the mean half-lives of GDH in lactating and dry cows. Because of the long half-life the small variations among individual cows are unlikely to affect the interpretation of increased plasma GDH activity.
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PMID:The half-life of glutamate dehydrogenase in plasma of dry and lactating dairy cows. 52 24

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

The characteristic spectra of glutamate dehydrogenase in the endosperm, embryo and pericarp of the developing seed, in the organs of the seedling (scutellum, root, mesocotyle, coleoptyle, leaf and root parenchyma of stem and ear) appear to be due to the differential activity of the genes controlling the enzyme synthesis. The type of spectrum of the initial tissue is preserved in the in vitro culture. The nature of organ specificity is discussed with respect to supposed mechanism of the formation of GDH isozyme spectrum.
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PMID:[Organ specific spectra of the glutamate dehydrogenase of corn, Zea mays L]. 69 80

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

Measurements of the deaminating activity of NAD-dependent glutamate dehydrogenase (NAD-GDH) in Pseudomonas aeruginosa strain 8602 (PAC 1) showed an initially constant rate that gave way to a 3.5-fold increased rate on prolonged incubation. Only the faster rate was observed when assay mixtures were preflushed with nitrogen or were treated with the detergent Triton X-100. Comparison of the intracellular distribution of NAD-GDH with marker enzymes showed it to be associated with the cytoplasmic membrane. The results suggest that NAD-GDH may be linked to oxygen through an electron-transport system.
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PMID:NAD-dependent glutamate dehydrogenase from Pseudomonas aeruginosa is a membrane-bound enzyme. 131 Dec 77

Glutamate, glutamine, and ammonia pool size have been determined in two S. cerevisiae strains (GOGAT+ and GOGAT-) growing under ammonia excess and limitation at a dilution rate of 0.10/h. The biomass levels and glutamate dehydrogenase NADPH-dependent (NADPH-GDH) activities were also measured for both strains. The strain that lacks GOGAT activity showed lower levels of metabolites under both media and lower levels of biomass under carbon limitation (ammonia excess) compared to the GOGAT+ strain. Under nitrogen limitation, the biomass level was the same for both strains, but GOGAT- changed from rounded to ellipsoidal cells.
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PMID:Ammonia assimilation in S. cerevisiae under chemostatic growth. 132 53

A Saccharomyces cerevisiae glutamate auxotroph, lacking NADP-glutamate dehydrogenase (NADP-GDH) and glutamate synthase (GOGAT) activities, was complemented with a yeast genomic library. Clones were obtained which still lacked NADP-GDH but showed GOGAT activity. Northern analysis revealed that the DNA fragment present in the complementing plasmids coded for a 1.5kb mRNA. Since the only GOGAT enzyme so far purified from S. cerevisiae is made up of a small and a large subunit, the size of the mRNA suggested that the cloned DNA fragment could code for the GOGAT small subunit. Plasmids were purified and used to transform Escherichia coli glutamate auxotrophs. Transformants were only recovered when the recipient strain was an E. coli GDH-less mutant lacking the small GOGAT subunit. These data show that we have cloned the structural gene coding for the yeast small subunit (GUS2). Evidence is also presented indicating that the GOGAT enzyme which is synthesized in the E. coli transformants is a hybrid comprising the large E. coli subunit and the small S. cerevisiae subunit.
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PMID:Cloning of a yeast gene coding for the glutamate synthase small subunit (GUS2) by complementation of Saccharomyces cerevisiae and Escherichia coli glutamate auxotrophs. 134 1

Corynebacterium callunae (NCIB 10338) grows faster on glutamate than ammonia when used as sole nitrogen sources. The levels of glutamine synthetase (GS; EC 6.3.1.2) and glutamate synthase (GOGAT; EC 1.4.1.13) of C. callunae were found to be influenced by the nitrogen source. Accordingly, the levels of GS and GOGAT activities were decreased markedly under conditions of ammonia excess and increased under low nitrogen conditions. In contrast, glutamate dehydrogenase (GDH; EC 1.4.1.4) activities were not significantly affected by the type or the concentration of the nitrogen source supplied. The carbon source in the growth medium could also affect GDH, GS and GOGAT levels. Of the carbon sources tested in the presence of 2 mM or 10 mM ammonium chloride as the nitrogen source pyruvate, acetate, fumarate and malate caused a decrease in the levels of all three enzymes as compared with glucose. GDH, GS and GOGAT levels were slightly influenced by aeration. Also, the enzyme levels varied with the growth phase. Methionine sulfoximine, an analogue of glutamine, markedly inhibited both the growth of C. callunae cells and the transferase activity of GS. The apparent Km values of GDH for ammonia and glutamate were 17.2 mM and 69.1 mM, respectively. In the NADPH-dependent reaction of GOGAT, the apparent Km values were 0.1 mM for alpha-ketoglutarate and 0.22 mM for glutamine.
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PMID:The effect of various culture conditions on the levels of ammonia assimilatory enzymes of Corynebacterium callunae. 135 48

In extracts from vegetative Dictyostelium discoideum V12 the basal NAD-dependent glutamate dehydrogenase (NAD-GDH) activity was low, but it increased on standing at 4 degrees C. When 0.1 mM-AMP was included in the assay mix, enzyme activity was stimulated nearly 30-fold. As the extract was allowed to age, the enzyme rapidly lost its ability to be stimulated by AMP. The response of NAD-GDH to AMP was also dependent on the stage of morphogenesis. The ratios of NAD-GDH activity assayed with and without AMP (+AMP/-AMP ratios) in freshly prepared extracts from cells at 0, 4, 8 and 12 h of development were similar, but declined later in morphogenesis. The +AMP/-AMP ratio decreased sharply during activation at 4 degrees C in extracts from cells at 0, 4, 16 and 20 h of development. By contrast, extracts from cells starved for 8 and 12 h remained more responsive to AMP throughout activation. Analysis of Western blots showed that vegetative NAD-GDH did not undergo any detectable proteolytic cleavage during 96 h of activation at 4 degrees C. Also, no change in molecular mass appeared to take place within the cells until culmination (20-24 h), when some breakdown products appeared. Activation of NAD-GDH also occurred in D. discoideum strains NC4 and AX3, and in D. mucoroides. In addition, the enzyme from these four strains was stimulated by AMP and the +AMP/-AMP ratio declined with similar kinetics during activation. The enzyme from Polysphondylium violaceum was not activated on standing, but it was stimulated by AMP. The effect of activation of NAD-GDH is discussed in relation to a postulated catabolic role for this enzyme.
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PMID:The effect of AMP on the NAD-dependent glutamate dehydrogenase during activation and morphogenesis in the cellular slime moulds. 140 93

The am8 mutant of Neurospora crassa is shown to have a double base-pair change, GTG for the normal TAG, at the 3' end of the second intron of the am (NADP-specific glutamate dehydrogenase, GDH) gene. The greater part of the mutant am transcript accumulates as two fragments hybridising to probes for sequences respectively upstream and downstream of the 5' end of the intron. Two processed transcripts approximating to normal full length mRNA were identified. In one the second intron was intact; in the other the second intron was spliced out through the use of an AAG sequence, 20 base-pairs into the third exon, as a 3' acceptor site. A GAG sequence, only four base-pairs downstream from the normal acceptor site, does not appear to be used.
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PMID:Alternative modes of mRNA processing in a 3' splice site mutant of Neurospora crassa. 153 88


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