RT Journal Article SR Electronic(1) A1 Vichido, Irma A1 Mora, Yolanda A1 Quinto, Carmen A1 Palacios, Rafael A1 Mora, JaimeYR 1978 T1 Nitrogen Regulation of Glutamine Synthetase in Neurospora crassa JF Microbiology, VO 106 IS 2 SP 251 OP 259 DO https://doi.org/10.1099/00221287-106-2-251 PB Microbiology Society, SN 1465-2080, AB A higher activity of glutamine synthetase (EC 6.3.1.2) was found in Neurospora crassa when NH4 + was limiting as nitrogen source than when glutamate was limiting. When glutamate, glutamine or NH4 +were in excess, a lower activity was found. Immunological titration and sucrose gradient sedimentation of the enzyme established that under all these conditions enzyme activity corresponded to enzyme concentration and that the octamer was the predominant oligomeric form. When N. crassa was shifted from nitrogen-limiting substrates to excess product as nitrogen source, the concentration of glutamine synthetase was adjusted with kinetics that closely followed dilution by growth. When grown on limiting amounts of glutamate, a lower oligomer was present in addition to the octameric form of the enzyme. When the culture was shifted to excess NH4 +, glutamine accumulated at a high rate; nevertheless, there was only a slow decrease in enzyme activity and no modification of the oligomeric pattern., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-106-2-251