Peptidase activities in Saccharomyces cerevisiae.

At least four distinct aminopeptidase activities and a single dipeptidase activity were found in cell extracts of a leucine-lysine auxotroph of Saccharomyces cerevisiae. The assay for peptidase activity involved polyacrylamide gel electrophoresis followed by an enzyme-coupled activity staining procedure. The aminopeptidases had largely overlapping specificities but could be distinguished from one another by their electrophoretic mobilities and activities toward different peptide substrates. Substrates tested included both free and blocked di- and tripeptides and amino acid derivatives.