Regulation of accumulation of ammonium-inducible glutamate dehydrogenase catalytic activity and antigen during the cell cycle of fully induced, synchronous Chlorella sorokiniana cells.
By use of a rocket immunoelectrophoresis-activity stain procedure, it was shown that catalytic activity of an ammonium-inducible nicotinamide adenine dinucleotide phosphate-specific glutamate dehydrogenase (NADP-GDH) was accompanied by a coincident increase in enzyme antigen during the cell cycle of preinduced synchronous Chlorella sorokiniana cells growing in the continuous presence of ammonia. Between the fourth and fifth hours of the G-1 phase of the cell cycle, a three- to fourfold increase in linear accumulation of enzyme antigen was observed. Pulse-chase studies with [35S]sulfate, coupled with a specific indirect immunoadsorption procedure for enzyme antigen, showed that NADP-GDH antigen undergoes continuous degradation (i.e., a half-life of 88 to 110 min) during its linear pattern of accumulation during the cell cycle. The apparent half-life of the enzyme increased by approximately 23% of the 4.5-h positive rate change in antigen accumulation during the cell cycle. This increase in half-life is insufficient in itself to account for the large change in rate of NADP-GDH antigen accumulation. The data from immunoelectrophoresis, pulse-chase, and initial 35S incorporation rate experiments taken together support the inference that changes in the rate of NADP-GDH synthesis are primarily responsible for the accumulation patterns of NADP-GDH activity during the C. sorokiniana cell cycle.
D000645:Ammonium Sulfate; D000942:Antigens, Bacterial; D002453:Cell Cycle; D002708:Chlorella / Q000166:cytology / Q000201:enzymology*; D004790:Enzyme Induction; D005969:Glutamate Dehydrogenase / Q000276:immunology / Q000378:metabolism*; D006207:Half-Life; D007700:Kinetics; D009249:NADP / Q000494:pharmacology
D000942:Antigens, Bacterial; D009249:NADP; D005969:Glutamate Dehydrogenase; D000645:Ammonium Sulfate