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 NAC (nitrogen assimilation control) protein from Klebsiella aerogenes is a LysR-like regulator for transcription of several operons involved in nitrogen metabolism, and couples the transcription of these sigma 70-dependent operons to regulation by the sigma 54-dependent NTR system. NAC activates expression of operons (e.g. histidine utilization, hut), allowing use of poor nitrogen sources, and represses expression of operons (e.g. glutamate dehydrogenase, gdh) allowing assimilation of the preferred nitrogen source, ammonium. NAC is both necessary and sufficient to activate transcription, but the expression of the nac gene is totally dependent on the central nitrogen regulatory system (NTR) and RNA polymerase carrying the sigma 54 sigma factor (RNAP sigma 54). Nitrogen starvation signals the NTR system to transcribe nac, and NAC activates the transcription of hut, put (proline utilization), and urease. NAC does not affect the transcription of RNAP sigma 54-dependent operons like ginA or nifLA, which respond directly to the NTR system, but activates transcription of RNAP sigma 70-dependent operons. Thus NAC acts as a bridge between RNAP sigma 70-dependent operons like hut and the RNAP sigma 54-dependent NTR system. The activation of operons like hut by NAC in response to nitrogen starvation is at least superficially similar to their activation by CAP-cAMP in response to carbon and energy starvation.
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PMID:The role of the NAC protein in the nitrogen regulation of Klebsiella aerogenes. 166 20

The effect of cAMP on the intracellular levels of five enzymes concerned with the interconversion of glutamate and glutamine in E. coli has been examined. Cyclic AMP added to the culture medium increases the levels of glutamate dehydrogenase (EC 1.4.1.4) and glutamine synthetase (EC 6.3.1.2); it decreases the levels of glutamate synthase (EC 1.4.1.X), and glutaminase A (EC 3.5.1.2). Cyclic AMP did not affect the level of glutaminase B (EC 3.5.1.2). These alterations in enzyme levels by cAMP require cyclic AMP receptor protein, since the levels of these enzymes were unchanged by cAMP in a mutant lacking this receptor. Chloramphenicol also abolished the effects of cAMP, a result that implies protein synthesis is necessary for these changes in enzyme levels to occur. The reciprocal effects of cAMP on the levels of these enzymes may play an important role in the cellular regulation of nitrogen metabolism.
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PMID:Adenosine 3':5'-cyclic monophosphate control of the enzymes of glutamine metabolism in Escherichia coli. 440 45

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

Chloramphenicol inhibits growth of C. intermedius C3 along with glutamic acid excretion, isocitrate dehydrogenase, glutamate dehydrogenase and the percentage of glutamic acid excreting colonies in solid medium. Repression of isocitrate dehydrogenase and glutamate dehydrogenase may explain the observed decrease in extracellular glutamic acid accumulation even when media were supplemented with 2-oxoglutarate, a known inducer of excretion in C. intermedius C3.
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PMID:[Influence of chloramphenicol on glutamic acid excretion in citrobacter intermedius C3 (author's transl)]. 611 15