Increase in Activity for the C-Terminal Pro-X Bond by Site-directed Mutagenesis of Gly137 to Ala in Carboxypeptidase Z

A mutant carboxypeptidase Z from Absidia zychae in which Glyl37 was replaced by Ala by site-directed mutagenesis was constructed and expressed in Saccharomyces cerevisiae YPH250. The mutant enzyme hydrolyzed C-terminal Pro-X bonds (X = amino acid) more efficiently than the wild-type enzyme and sequentially released amino acids from the C-termini of oligopeptides.