Porcine carboxypeptidase B. I. Affinity chromatography and specificity

Porcine carboxypeptidase B (peptidyl-l-lysine hydrolase, EC 3.4.2.2), was found to possess in addition to its known specificity toward basic substrates an intrinsic activity with specificity similar to that of carboxypeptidase A (peptidyl-l-amino acid hydrolase, EC 3.4.2.1). Affinity chromatography using a water insoluble derivative of the inhibitor d-Ala-l-Arg was employed in order to establish that the activities toward non-basic substrates are intrinsic and not due to contamination present in the commercial porcine carboxypeptidaes B.