Hormone (pheromone) processing enzymes in yeast. The carboxy-terminal processing enzyme of the mating pheromone alpha-factor, carboxypeptidase ysc alpha, is absent in alpha-factor maturation-defective kex1 mutant cells.

Carboxy-terminal processing of the mating pheromone alpha-factor of the yeast Saccharomyces cerevisiae has been assumed to be due to the action of carboxypeptidase ysc alpha [(1985) EMBO J. 4, 173-177]. Here it is shown that a mutant (kex1) defective in alpha-factor maturation is defective in carboxypeptidase ysc alpha activity, indicating that the enzyme is indeed the processing catalyst. It is proposed that carboxypeptidase ysc alpha is the product of the KEX1 gene.