CPY is a metal-free carboxypeptidase from yeast with broad specificity . In addition to exopeptidase activity at acid pH, the enzyme is an effective esterase at alkaline pH. N-alpha-acetyl-L-tyrosine ethyl ester is hydrolyzed faster by CPY than by chymotrypsin. These observations suggested that the immobilized form of the enzyme would be of value in removing ester groups from the C-terminal ends of peptides. In this report we describe sequential synthesis using I-CPY and alpha-COOH deblocking of peptides made by conventional methods.