Abstract
Fifty-nine mutants with reduced ability to cleave the chymotrypsin substrate N-acetyl-DL-phenylalanine β-naphthyl ester have been isolated in S. cerevisiae. All have reduced levels of one or more of the three well-characterized proteinases in yeast. All have reduced levels of proteinase C (carboxy-peptidase Y). These mutations define 16 complementation groups.