Glutamine Synthetase and Glutamate Synthase Activities During Growth and Sporulation in Bacillus subtilis

SUMMARY: Glutamine synthetase in Bacillus subtilis 168 was repressed to a greater extent by l-glutamine or l-arginine than by ammonia when each was used as sole nitrogen source. It was derepressed when either l-glutamate or nitrate was used as nitrogen source. Glutamate synthase was repressed by l-glutamate or l-arginine and, to a lesser extent, by l-glutamine but was derepressed during growth with ammonia or nitrate. Glutamine synthetase activity was unaltered during the onset of sporulation. Glutamate synthase activity, however, underwent a small and apparently transient increase in bacteria induced to sporulate by nitrogen limitation.