Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Washed-cell preparations of Mycobacterium tuberculosis strain H37Ra and M. smegmatis 607 grown in Sauton's medium demonstrated a lag in glutamate oxidation. Washed-cell preparations of M. fortuitum and M. phlei oxidized glutamate immediately and in a linear fashion. Glutamate was oxidized without a lag by washed cells of M. tuberculosis H37Ra and M. smegmatis 607 harvested from a modified medium containing glutamate. Chloramphenicol inhibited the oxidation of glutamate by washed cells grown in the absence of glutamate. These findings suggested the induction of either an enzyme system for glutamate oxidation or a glutamate transport system. The activity of glutamic dehydrogenase was not significantly greater in extracts prepared from cells grown with glutamate. However, the initial rate of glutamate uptake by induced cells was three to four times higher than in noninduced cells. The induction of the glutamate transport system in M. tuberculosis H37Ra and M. smegmatis 607 was shown to parallel the induction of glutamate oxidation. After a 60-min lag, the inducible glutamate transport system appeared. Chloramphenicol prevented the induction of glutamate uptake, although the antibiotic had no effect on glutamate uptake by previously induced cells. Some of the properties of this glutamate uptake system are described.
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PMID:Inducible glutamate transport in Mycobacteria and its relation to glutamate oxidation. 602 4

Glutamine synthetase from Pseudomonas aeruginosa is regulated by repression/derepression of enzyme synthesis and by adenylylation/deadenylylation control. High levels of deadenylylated biosynthetically active glutamine synthetase were observed in cultures growing with limiting amounts of nitrogen while synthesis of the enzyme was repressed and that present was adenylylated in cultures with excess nitrogen. NADP- and NAD-dependent glutamate dehydrogenase could be separated by column chromatography and showed molecular weights of 110,000 and 220,000, respectively. Synthesis of the NADP-dependent glutamate dehydrogenase is repressed under nitrogen limitation and by growth on glutamate. In contrast, NAD-dependent glutamate dehydrogenase is derepressed by glutamate. Glutamate synthase is repressed by glutamate but not by excess nitrogen.
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PMID:The enzymes of the ammonia assimilation in Pseudomonas aeruginosa. 610 51

Urease and glutamine synthetase activities in Selenomonas ruminantium strain D were highest in cells grown in ammonia-limited, linear-growth cultures or when certain compounds other than ammonia served as the nitrogen source and limited the growth rate in batch cultures. Glutamate dehydrogenase activity was highest during glucose (energy)-limited growth or when ammonia was not growth limiting. A positive correlation (R = 0.96) between glutamine synthetase and urease activities was observed for a variety of growth conditions, and both enzyme activities were simultaneously repressed when excess ammonia was added to ammonia-limited, linear-growth cultures. The glutamate analog methionine sulfoximine (MSX), inhibited glutamine synthetase activity in vitro, but glutamate dehydrogenase, glutamate synthase, and urease activities were not affected. The addition of MSX (0.1 to 100 mM) to cultures growing with 20 mM ammonia resulted in growth rate inhibition that was dependent upon the concentration of MSX and was overcome by glutamine addition. Urease activity in MSX-inhibited cultures was increased significantly, suggesting that ammonia was not the direct repressor of urease activity. In ammonia-limited, linear-growth cultures, MSX addition resulted in growth inhibition, a decrease in GS activity, and an increase in urease activity. These results are discussed with respect to the importance of glutamine synthetase and glutamate dehydrogenase for ammonia assimilation under different growth conditions and the relationship of these enzymes to urease.
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PMID:Regulation of urease and ammonia assimilatory enzymes in Selenomonas ruminantium. 611 7

384 hospitalized patients of both sexes were classified into drinkers and non-drinkers according to clinical criteria. On admission, we measured four blood parameters : glutamate dehydrogenase, gamma glutamyl transferase, aspartate aminotransferase and the mean corpuscular volume. the discriminating power of these laboratory parameters was evaluated by descriptive statistical tests and by the determination of their positive and negative predictive value. Glutamate dehydrogenase appears to present a sensitivity almost equivalent to that of gamma glutamyl transferase and a better specificity : this results in a more positive predictive value. The two other laboratory parameters are less discriminating.
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PMID:[Role of glutamate dehydrogenase in the biological detection of excessive drinkers]. 613 49

The relationship between chloramphenicol production and nitrogen metabolism in Streptomyces venezuelae was examined in stirred jar cultures under pH control. Nitrogen sources that supported rapid biomass accumulation gave low rates of antibiotic synthesis during growth. This was consistent with a general incompatibility between fast growth and high yields of chloramphenicol. In media where the growth rate was reduced below the attainable maximum by the rate at which nitrogen could be assimilated, chloramphenicol production was associated with biomass accumulation. Enzymes that are potentially associated with nitrogen assimilation pathways were assayed in cultures supplied with nitrogen sources supporting markedly different growth rates. The results indicated that glutamine synthetase and alanine dehydrogenase levels were relatively insensitive to changes in growth rate and nitrogen source depletion. Glutamate dehydrogenase and glutamate synthase, on the other hand, showed high activity in cultures assimilating ammonium nitrogen and markedly decreased activity with poorer nitrogen sources or when ammonium was depleted. If chloramphenicol biosynthesis is coordinately controlled by mechanisms that regulate nitrogen assimilation, glutamate synthase and glutamate dehydrogenase are the most likely enzymes that manifest the regulatory linkage.
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PMID:Nitrogen metabolism and chloramphenicol production in Streptomyces venezuelae. 614 5

Glutamate dehydrogenase activity was determined in mitochondrial preparations from rat ventral prostate and rat kidney. Kinetic parameters of the ventral prostate enzyme were comparable to those for the kidney enzyme. Glutamate dehydrogenase activity in the direction of glutamate oxidative deamination was inhibited by alpha-ketoglutarate. However, the characteristics of alpha-ketoglutarate inhibition indicated that glutamate oxidation via glutamate dehydrogenase can occur at in vivo prostatic alpha-ketoglutarate levels. These results suggest that glutamate dehydrogenase activity in prostate may provide a continuous source of alpha-ketoglutarate for aspartate transamination to oxalacetate and ultimate citrate synthesis. In addition prostate mitochondria are able to couple the glutamic dehydrogenase reaction to aspartate aminotransferase. Under these conditions aspartate in the presence of glutamate and acetyl coenzyme A will result in a net synthesis of citrate. Consequently we propose an aspartate-glutamate pathway for citrate synthesis in prostate.
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PMID:Glutamate dehydrogenase and a proposed glutamate-aspartate pathway for citrate synthesis in rat ventral prostate. 615 Jan 22

Glutamate synthase catalyzes glutamate formation from 2-oxoglutarate plus glutamine and plays an essential role when glutamate biosynthesis by glutamate dehydrogenase is not possible. Glutamate synthase activity has been determined in a number of Neurospora crassa mutant strains with various defects in nitrogen metabolism. Of particular interest were two mutants phenotypically mute except in an am (biosynthetic nicotinamide adenine dinucleotide phosphate-glutamate dehydrogenase deficient, glutamate requiring) background. These mutants, i and en-am, are so-called enhancers of am; they have been redesignated herein as en(am)-1 and en(am)-2, respectively. Although glutamate synthase levels in en(am)-1 were essentially wild type, the en(am)-2 strain was devoid of glutamate synthase activity under all conditions examined, suggesting that en(am)-2 may be the structural locus for glutamate synthase. Regulation of glutamate synthase occurred to some extent, presumably in response to glutamate requirements. Glutamate starvation, as in am mutants, led to enhanced activity. In contrast, glutamine limitation, as in gln-1 mutants, depressed glutamate synthase levels.
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PMID:Glutamate synthase levels in Neurospora crassa mutants altered with respect to nitrogen metabolism. 615 51

A certain topographic parallelism between the distribution of histochemically (TIMM staining) identified zinc and putative glutamatergic structures in the rat brain was demonstrated. Glutamate dehydrogenase as a zinc containing protein is in consideration to be an enzyme synthesizing transmitter glutamate. In a low concentration range externally added zinc ions (10(-9) to 10(-7) M) induced an increase in the activity of glutamate dehydrogenase (GDH) originating from rat hippocampal formation, neocortex, and cerebellum up to 142.4%. With rising molarity of Zn(II) in the incubation medium, the enzyme of hippocampal formation and cerebellum showed a biphasic course of activation. Zinc ions of a concentration higher than 10(-6) M caused a strong inhibition of GDH. The effect of Zn(II) on GDH originating from spinal ganglia and liver led only to a decrease of enzyme activity. These results are discussed in connection with a functional correlation between zinc and putatively glutamatergic system.
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PMID:Zinc and glutamate dehydrogenase in putative glutamatergic brain structures. 619 63

The activities of various ammoniagenic, gluconeogenic, and glycolytic enzymes were measured in the renal cortex and also in the liver of rats made diabetic with streptozotocin. Five groups of animals were studied: normal, normoglycemic diabetic (insulin therapy), hyperglycemic, ketoacidotic, and ammonium chloride treated rats. Glutaminase I, glutamate dehydrogenase, glutamine synthetase, phosphoenolpyruvate carboxykinase (PEPCK), hexokinase, phosphofructokinase, fructose-1,6-diphosphatase, malate dehydrogenase, malic enzyme, and lactate dehydrogenase were measured. Renal glutaminase I activity rose during ketoacidosis and ammonium chloride acidosis. Glutamate dehydrogenase in the kidney rose only in ammonium chloride treated animals. Glutamine synthetase showed no particular variation. PEPCK rose in diabetic hyperglycemic animals and more so during ketoacidosis and ammonium chloride acidosis. It also rose in the liver of the diabetic animals. Hexokinase activity in the kidney rose in diabetic insulin-treated normoglycemic rats and also during ketoacidosis. The same pattern was observed in the liver of these diabetic rats. Renal and hepatic phosphofructokinase activities were elevated in all groups of experimental animals. Fructose-1,6-diphosphatase and malate dehydrogenase did not vary significantly in the kidney and the liver. Malic enzyme was lower in the kidney and liver of the hyperglycemic diabetic animals and also in the liver of the ketoacidotic rats. Lactate dehydrogenase fell slightly in the liver of diabetic hyperglycemic and NH4Cl acidotic animals. The present study indicates that glutaminase I is associated with the first step of increased renal ammoniagenesis during ketoacidosis. PEPCK activity is influenced both by hyperglycemia and ketoacidosis, acidosis playing an additional role. Insulin appears to prevent renal gluconeogenesis and to favour glycolysis. The latter would seem to remain operative in hyperglycemic and ketoacidotic diabetic animals.
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PMID:Renal enzymes during experimental diabetes mellitus in the rat. Role of insulin, carbohydrate metabolism, and ketoacidosis. 623 75

Glutamic acid is synthesized in enteric bacteria by either glutamate dehydrogenase or by the coupled activities of glutamate synthase and glutamine synthetase. A hybrid plasmid containing a fragment of the Salmonella typhimurium chromosome cloned into pBR328 restores growth of glutamate auxotrophs of S. typhimurium and Escherichia coli strains which have mutations in the genes for glutamate dehydrogenase and glutamate synthase. A 2.2-kilobase pair region was shown by complementation analysis, enzyme activity measurements, and the maxicell protein synthesizing system to carry the entire glutamate dehydrogenase structural gene, gdhA. Glutamate dehydrogenase encoded by gdhA carried on recombinant plasmids was elevated 5- to over 100-fold in S. typhimurium or E. coli cells and was regulated in both organisms. The gdhA promoter was located by recombination studies and by the in vitro fusion to, and activation of, a promoter-deficient galK gene. Additionally, S. typhimurium gdhA DNA was shown to hybridize to single restriction fragments of chromosomes from other enteric bacteria and from Saccharomyces cerevisiae.
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PMID:Cloning and characterization of gdhA, the structural gene for glutamate dehydrogenase of Salmonella typhimurium. 636 Sep 94


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