Glutamine utilization in both the arginine-specific and pyrimidine-specific carbamoyl phosphate synthase enzymes of eurospora crassa.

As glutamine-dependent carbamoyl phasphate synthetase (CPS) activity in some organisms is composed of a glutaminase and an ammonium-dependent CPS, CPS- mutants in Neurospora crassa were examined for glutamine- and ammonium-dependent CPS activities. No evidence was found that the genetic location of these two functions were separable. This is discussed with reference to the close genetic proximity of the CPSpyr and aspartate carbamoyltransferase (ACT) structural gene (pyr-3) and the arg-2 gene which appears to specify a subunit responsible for glutamine utilisation in CPSarg.