Turnover of ammonium-inducible glutamate dehydrogenase during induction and its rapid inactivation after removal of inducer from Chlorella sorokiniana cells.
AUTOR(ES)
Bascomb, N F
RESUMO
When ammonia was removed from Chlorella sorokiniana cells, which contain an ammonium-inducible nicotinamide adenine dinucleotide phosphate-specific glutamate dehydrogenase (NADP-GDH), the activity of this enzyme decayed with a half-life of approximately 8 min. By use of rocket immunoelectrophoresis, indirect immunoprecipitation, and indirect immunoadsorption (coupled with pulse-chase experiments with 35S-labeled sulfate), the rapid initial loss in activity was shown to be due to enzyme inactivation rather than degradation of NADP-GDH antigen. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of immunoprecipitates obtained with anti-NADP-GDH immunoglobulin G showed that enzyme inactivation is accompanied by the conversion of enzyme subunits (Mr = 59,000) to a protein with a molecular weight of 118,000. Because this protein was stable during boiling and in the presence of sodium dodecyl sulfate and high concentrations of mercaptoethanol or dithiothreitol, it was tentatively assumed to be a covalently linked dimer of enzyme subunits. Pulse-chase experiments showed that total NADP-GDH antigen was subject to rapid degradation (t 1/2 = 88 min) in induced cells, and the same degradation rate was maintained after removal of ammonia from induced cells.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=217127Documentos Relacionados
- Regulation of accumulation of ammonium-inducible glutamate dehydrogenase catalytic activity and antigen during the cell cycle of fully induced, synchronous Chlorella sorokiniana cells.
- Different Rates of Synthesis and Degradation of Two Chloroplastic Ammonium-Inducible NADP-Specific Glutamate Dehydrogenase Isoenzymes during Induction and Deinduction in Chlorella sorokiniana Cells 1
- Evidence for messenger ribonucleic acid of an ammonium-inducible glutamate dehydrogenase and synthesis, covalent modification, and degradation of enzyme subunits in uninduced Chlorella sorokiniana cells.
- Light Requirement for Induction and Continuous Accumulation of an Ammonium-Inducible NADP-Specific Glutamate Dehydrogenase in Chlorella1
- Purification and properties of the inducible nicotinamide adenine dinucleotide phosphate-specific glutamate dehydrogenase from Chlorella sorokiniana.