Ammonia assimilation in the fission yeast Schizosaccharomyces pombe 972.
Glutamine synthetase (GS) activity of Schizosaccharomyces pombe 972 was high in ammonia-limited cultures, low in phosphate- and sulphate-limited cultures and not detected in glucose-limited cultures. When ammonia was 'pulsed' into an ammonia-limited culture then GS activity decreased at a rate faster than that calculated if enzyme synthesis ceased and enzyme was diluted out by growth. Enzyme activity increased in ammonia-starved, phosphate-limited cultures and in the ammonia 'pulse' system when the added ammonia had been utilised. These increases in enzyme activity were prevented by the presence of 100 mug/ml cycloheximide. GS activity was inversely related to the intracellular concentration of glutamate.
D000641:Ammonia / Q000378:metabolism*; D001203:Ascomycota / Q000378:metabolism*; D003513:Cycloheximide / Q000494:pharmacology; D005969:Glutamate Dehydrogenase / Q000378:metabolism; D005970:Glutamate Synthase / Q000378:metabolism; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism; D005971:Glutamates / Q000378:metabolism; D005973:Glutamine / Q000378:metabolism; D007656:Ketoglutaric Acids / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism; D012568:Schizosaccharomyces / Q000378:metabolism*
D005971:Glutamates; D007656:Ketoglutaric Acids; D010710:Phosphates; D005973:Glutamine; D000641:Ammonia; D003513:Cycloheximide; D005970:Glutamate Synthase; D005969:Glutamate Dehydrogenase; D005974:Glutamate-Ammonia Ligase