Determination of C-terminal sequences by digestion with serine carboxypeptidases: The influence of enzyme specificity

Abstract

It is demonstrated that C-terminal sequence determinations of a number of proteins and peptides by digestion with serine carboxypeptidases often require use of different reaction conditions and/or use of carboxypeptidases with different specificities. The commonly utilized carboxypeptidase Y from yeast with preference for hydrophobic amino acid residues is conveniently supplemented by carboxypeptidase II from amlt which includes Lys and Arg in its specificity range. This renders it particularly suitable for C-terminal digestion of tryptic peptides. In some cases a phenylmercuric chloride modified derivative of carboxypeptidase Y which has a decreased preference for hydrophobic amino acid residues can be used with advantage. © 1987 Carlbserg Laboratory.