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:1.4.3.11 (glutamate dehydrogenase)
4,437 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied the physiology of cells of Klebsiella aerogenes containing the structural gene for glutamine synthetase (glnA) of Escherichia coli on an episome. The E. coli glutamine synthetase functioned in cells of K. aerogenes in a manner similar to that of the K. aerogenes enzyme: it allowed the level of histidase to increase and that of glutamate dehydrogenase to decrease during nitrogen-limited growth. The phenotype of mutations in the glnA site was restored to normal by the introduction of the episomal glnA+ gene. These results are consistent with the hypothesis that glutamine synthetase regulates the function of its own structural gene.
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PMID:Regulation of enzyme formation in Klebsiella aerogenes by episomal glutamine synthetase of Escherichia coli. 0 31

We have partially characterized the biochemical parameters of glutamine synthetase from Klebsiella pneumoniae and have shown that the differential affinity of adenylylated and unadenylylated glutamine synthetase for adenosine diphosphate provides a convenient means of determining the adenylylation state. Using this assay procedure, we examined the relationship between the adenylylation state and the expression of other genes involved in nitrogen assimilation. We observed no correlation between the adenylylation state and the expression of histidase, glutamine synthetase, glutamate synthase, glutamate dehydrogenase, and urease in aerobic cultures.
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PMID:Relation between the adenylylation state of glutamine synthetase and the expression of other genes involved in nitrogen metabolism. 3 15

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

A positive, genetic selection against the activity of the nitrogen regulatory (NTR) system was used to isolate insertion mutations affecting nitrogen regulation in Klebsiella aerogenes. Two classes of mutation were obtained: those affecting the NTR system itself and leading to the loss of almost all nitrogen regulation, and those affecting the nac locus and leading to a loss of nitrogen regulation of a family of nitrogen-regulated enzymes. The set of these nac-dependent enzymes included histidase, glutamate dehydrogenase, glutamate synthase, proline oxidase, and urease. The enzymes shown to be nac independent included glutamine synthetase, asparaginase, tryptophan permease, nitrate reductase, the product of the nifLA operon, and perhaps nitrite reductase. The expression of the nac gene was itself highly nitrogen regulated, and this regulation was mediated by the NTR system. The loss of nitrogen regulation was found in each of the four insertion mutants studied, showing that loss of nitrogen regulation resulted from the absence of nac function rather than from an altered form of the nac gene product. Thus we propose two classes of nitrogen-regulated operons: in class I, the NTR system directly activates expression of the operon; in class II, the NTR system activates nac expression and the product(s) of the nac locus activates expression of the operon.
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PMID:Role of the nac gene product in the nitrogen regulation of some NTR-regulated operons of Klebsiella aerogenes. 197 23

In a previous study we demonstrated thirteen amino acids to be essential and two to be partially essential for lymphocyte proliferation. Arginine is one of the essential amino acids, and the highly purified arginase strongly inhibited lymphocyte proliferation. The modulation of lymphocyte growth by various amino acid-degrading enzymes was studied. Peripheral lymphocytes were cultured in RPMI 1640 with or without amino acid-degrading enzyme for 72 h. A total of 17 commercial L-amino acid-degrading enzymes were studied. At 10 micrograms/ml, both lysine decarboxylase and asparaginase completely inhibited lymphocyte proliferation, arginase resulted in 78% inhibition and tyrosinase 57% inhibition. Other enzymes inhibited less than 20% lymphocyte proliferation; they included alanine dehydrogenase, arginine decarboxylase, aspartase, glutamic decarboxylase, glutamic dehydrogenase, glutaminase, histidase, histidine decarboxylase, leucine dehydrogenase, phenylalanine decarboxylase, phenylalanine hydroxylase, tryptophanase, and tyrosine decarboxylase. All four enzymes that strongly inhibited lymphocyte proliferation degraded amino acids that are essential for lymphocyte growth.
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PMID:Modulation of lymphocyte proliferation by enzymes that degrade amino acids. 212 55

The nac (nitrogen assimilation control) gene from Klebsiella aerogenes, cloned in a low-copy-number cloning vector, restored the ability of K. aerogenes nac mutants to activate histidase and repress glutamate dehydrogenase formation in response to nitrogen limitation and to limit the maximum expression of the nac promoter. When present in Salmonella typhimurium, the K. aerogenes nac gene allowed the hut genes to be activated during nitrogen-limited growth. Thus, the nac gene encodes a cytoplasmic factor required for activation of hut expression in S. typhimurium during nitrogen-limited growth.
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PMID:Cloning of the Klebsiella aerogenes nac gene, which encodes a factor required for nitrogen regulation of the histidine utilization (hut) operons in Salmonella typhimurium. 225 73

During growth of Aspergillus nidulans in medium containing ammonium the specific activities of most enzymes involved in catabolism of nitrogen sources are low (ammonium repression). The gdhA10 lesion, which results in loss of nicotinamide adenine dinucleotide phosphate-linked glutamate dehydrogenase activity, has been shown to lead to partial relief of ammonium repression of three amidase enzymes as well as histidase. The areA102 lesion led to altered levels of these enzymes but did not greatly affect ammonium repression. The double mutant areA102,gdhA10 was almost completely insensitive to ammonium repression of two of the amidase enzymes and histidase. This suggests that an interaction between the areA and gdhA genes in determining responses to ammonium occurs. Growth of mycelium in medium containing l-glutamate has been found to result in lowered levels of all four enzymes, and this occurs in strains insensitive to ammonium repression. Very strong repression in all strains occurred during growth in medium containing l-glutamine. Relief of these repressive effects of glutamate and glutamine was blocked by cycloheximide. Glutamate and glutamine had similar effects on the production of extracellular protease activity, and growth on glutamine led to low levels of urate oxidase. In contrast to the above enzymes, nitrate reductase was insensitive to the effects of glutamine and glutamate, even though this enzyme is very sensitive to ammonium repression. Although other possibilities exist, it is suggested that there may be mechanisms of general control of nitrogen-catabolic enzymes other than ammonium repression.
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PMID:Effects of ammonium, L-glutamate, and L-glutamine on nitrogen catabolism in Aspergillus nidulans. 461 4

In Pseudomonas aeruginosa the formation of urease, histidase and some other enzymes involved in nitrogen assimilation is repressed by ammonia in the growth medium. The key metabolite in this process appears to be glutamine or a product derived from it, since ammonia and glutamate did not repress urease and histidase synthesis in a mutant lacking glutamine synthetase activity when growth was limited for glutamine. The synthesis of these enzymes was repressed in cells growing in the presence of excess glutamine. High levels of glutamine were also required for the derepression of NADP-dependent glutamate dehydrogenase formation in the glutamine synthetase-negative mutant.
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PMID:Nitrogen control in Pseudomonas aeruginosa: a role for glutamine in the regulations of the synthesis of nadp-dependent glutamate dehydrogenase, urease and histidase. 611 86

Mutant strains SU1, SU4, and US1 lacking glutamate synthase (GOGAT) activity were isolated from strains of P. aeruginosa for which histidine is a growth rate-limiting source of nitrogen. Strains SU1 and SU4 were unable to grow when a low concentration of ammonia and a variety of compounds, including histidine, were supplied as sole sources of nitrogen. A revertant of strain SU1, strain 39, produced no GOGAT but high levels of nicotinamide adenine dinucleotide-dependent glutamate dehydrogenase and had restored ability to grow on a limited number of nitrogen sources. Strain US1 grew at the same rate in histidine medium as did its parent; it was derepressed for glutamine synthase synthesis, and histidase was less sensitive to repression by ammonia than in the parent strain. We conclude that GOGAT is not essential for growth on histidine but high levels of glutamine synthase are required nd high levels of nicotinamide adenine dinucleotide-dependent glutamate dehydrogenase can sustain growth at low concentrations of ammonia in the absence of GOGAT.
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PMID:Growth of Pseudomonas aeruginosa mutants lacking glutamate synthase activity. 611 33

An amber mutation (glnA3711), the first nonsense mutation isolated in Klebsiella aerogenes, is described. When amber suppressors were present, the mutant made active glutamine synthetase which was more thermolabile than wild type, showing that glnA3711 lies in the structural gene for glutamine synthetase. Strains carrying the glnA3711 allele were unable to express nitrogen regulation of genes coding for histidase, asparaginase, and glutamate dehydrogenase unless amber suppressors were also present. These results support a model that expression of gene(s) from the glnA promoter is required for nitrogen regulation in K. aerogenes.
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PMID:A nonsense mutation in the structural gene for glutamine synthetase leading to loss of nitrogen regulation in Klebsiella aerogenes. 612 65


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