NEUROSPORA MUTANT LACKING AN ARGININE-SPECIFIC CARBAMYL PHOSPHOKINASE.

An arginine-requiring mutant of Neurospora lacks the carbamyl phosphokinase activity present in other strains. Although carbamyl phosphate, the product of this enzyme, is required in both arginine and pyrimidine synthesis, the enzymne appears to serve only the arginine pathway. A pyrimidine specific mode of carbamyl phosphate synthesis is inferred, although it has not yet been demonstrated.