Regulatory studies of L-glutamate dehydrogenase from Trypanosoma cruzi epimastigotes.
1. The specific activity of NADP-dependent L-glutamate dehydrogenase (GDH) from T. cruzi epimastigotes increased from 0.7 at early log-phase to 1.4 mumol/min/mg of protein at the stationary phase. 2. When T. cruzi cells were incubated in the presence of L-glutamate (0.08%), the GDH had a specific activity of 2.2, much higher than that of cells incubated in the presence of D-glucose (0.08%), which was 1.2 mumol/min/mg of protein. 3. The specific activity of NADP-dependent GDH from cells incubated in the presence of L-glutamate did not vary when the cells were treated with cycloheximide (100 ng/ml) or chloramphenicol (0.5 mg/ml). 4. The activity of the NAD-dependent GDH did not change in any of the situations described above. 5. AMP, ADP, ATP, citrate, isocitrate, oxaloacetate, fructose-1,6-diP, pyruvate, L-proline and L-arginine did not have any effect on the NADP-linked GDH activity. Product inhibition studies were done on the latter GDH activity.
D000818:Animals; D005947:Glucose / Q000494:pharmacology; D005969:Glutamate Dehydrogenase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D005971:Glutamates / Q000494:pharmacology; D018698:Glutamic Acid; D009243:NAD / Q000494:pharmacology; D009249:NADP / Q000494:pharmacology; D014349:Trypanosoma cruzi / Q000201:enzymology* / Q000254:growth & development
D005971:Glutamates; D009243:NAD; D018698:Glutamic Acid; D009249:NADP; D005969:Glutamate Dehydrogenase; D005947:Glucose