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)

Glutamate dehydrogenase becomes density labeled through the incorporation of deuterium and (15)N when detached oat leaves (Avena sativa var. Fulghum) are incubated in the presence of ammonia. The enzyme has been isolated by means of DEAE-cellulose chromatography, ammonium sulfate precipitation, isopycnic equilibrium centrifugation, and disc electrophoresis from leaves fed l-methionine-(35)S. Radioactivity is incorporated into isozyme 1 of glutamate dehydrogenase, whereas isozyme 2, detected only in the absence of ammonia, has not been labeled. Cycloheximide, chloramphenicol, puromycin, and 6-methyl purine inhibit the elevation of glutamate dehydrogenase by ammonia. It is suggested that the increase in glutamate dehydrogenase activity is due to de novo synthesis of isozyme 1.
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PMID:Evidence for Ammonium-dependent de Novo Synthesis of Glutamate Dehydrogenase in Detached Oat Leaves. 1665 11

The kinetics of accumulation (per milliliter of culture) of the alpha- and beta- subunits, associated with chloroplast-localized ammonium inducible nicotinamide adenine dinucleotide phosphate-specific glutamate dehydrogenase (NADP-GDH) isoenzymes, were measured during a 3 hour induction of synchronized daughter cells of Chlorella sorokiniana in 29 millimolar ammonium medium under photoautotrophic conditions. The beta-subunit holoenzyme(s) accumulated in a linear manner for 3 hours without an apparent induction lag. A 40 minute induction lag preceded the accumulation of the alpha-subunit holoenzyme(s). After 120 minutes, the alpha-subunit ceased accumulating and thereafter remained at a constant level (i.e. steady state between synthesis and degradation). From pulsechase experiments, using (35)SO(4) and immunochemical procedures, the rate of synthesis of the alpha-subunit was shown to be greater than the beta-subunit during the first 80 minutes of induction. The alpha- and beta-subunits had different rates of degradation during the induction period (t((1/2)) = 50 versus 150 minutes, respectively) and during the deinduction period (t((1/2)) = 5 versus 13.5 minutes) after removal of ammonium from the culture. During deinduction, total NADP-GDH activity decreased with a half-time of 9 minutes. Cycloheximide completely inhibited the synthesis and degradation of both subunits. A model for regulation of expression of the NADP-GDH gene was proposed.
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PMID:Different Rates of Synthesis and Degradation of Two Chloroplastic Ammonium-Inducible NADP-Specific Glutamate Dehydrogenase Isoenzymes during Induction and Deinduction in Chlorella sorokiniana Cells. 1666 21

Activities of nitrate reductase (NR; EC 1.6.6.1), nitrite reductase (NiR; EC 1.7.7.1), glutamine synthetase (GS; EC 6.3.1.2) and glutamate dehydrogenase (GDH; EC 1.4.1.3) were measured in cotyledons of sunflower (Helianthus annuus L. cv Peredovic) seedlings during germination and early growth under various external nitrogen sources. The presence of NO 3 (-) in the medium promoted a gradual increase in the levels of NR and NiR activities during the first 7 d of germination. Neither NR nor NiR activities were increased in a nitrogen-free medium or in media with either NH 4 (+) or urea as nitrogen sources. Moreover, the presence of NH 4 (+) did not abolish the NO 3 (-) -dependent appearance of NR and NiR activities. The increase of NR activity was impaired both by cycloheximide and chloramphenicol, which indicates that both cytoplasmic 80S and plastidic 70S ribosomes are involved in the synthesis of the NR molecule. By contrast, the appearance of NiR activity was only inhibited by cycloheximide, indicating that NiR seems to be exclusively synthesized on the cytoplasmic 80S ribosomes. Glutamine-synthetase activity was also strongly increased by external NO 3 (-) but not by NH 4 (+) or urea. The appearance of GS activity was more efficiently suppressed by cycloheximide than chloramphenicol. This indicates that GS is mostly synthesized in the cytoplasm. The cotyledons of the dry seed contain high levels of GDH activity which decline during germination independently of the presence or absence of a nitrogen source. Cycloheximide, but not chloramphenicol, greatly prevented the decrease of GDH activity.
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PMID:Development of nitrogen-assimilating enzymes in sunflower cotyledons during germination as affected by the exogenous nitrogen source. 2422 79