Carboxypeptidases

Abstract

This chapter focuses on carboxypeptidases, which hydrolyze peptides with a free COOH group on the adjacent peptide or ester bond; an additional free NH 2 -group is not necessary and can even inhibit the hydrolysis. Carboxypeptidase A acts on many proteins and peptides but C-terminal proline and basic amino acids are not hydrolyzed. Carboxypeptidase B hydrolyzes particularly rapidly C-terminal basic amino acids such as l -arginine, l -lysine or l -ornithine from natural or synthetic peptides or proteins. Yeast carboxypeptidase has only been obtained in partially purified form. Carboxypeptidases occur in many organs and are generally termed catheptic carboxypeptidases. In blood serum an enzyme distinct from carboxypeptidase B has been found; it hydrolyzes in particular C-terminal basic amino acids and bradykinin. In bacteria, molds and plants carboxypeptidases have been found.