Catalytic activity of carboxypeptidase B and of carboxypeptidase Y with anisylazoformyl substrates

Anisylazoformyllysine (CH3OC6H4---N=N---CO-Lys-OH) is rapidly hydrolyzed at the acyl-lysine linkage by the zinc-enzyme porcine carboxypeptidase B. The catalytic reaction is readily monitored spectro-photometrically by disappearance of the intense absorption (348.5 nm, 18400) of the azo chromophore, which chemically fragments after substrate cleavage. Carboxypeptidase Y has no activity toward this type of substrate.