COMPARISON OF THE BEHAVIOR OF CHYMOTRYPSIN AND CATHEPSIN-B TOWARDS PEPTIDYL DIAZOMETHYL KETONES

Chymotrypsin is not inactivated by benzyloxycarbonyl-phenylalanyl diazomethyl ketone although disappearance of the diazo group can be followed spectroscopically. It is also inert to various dipeptide derivatives. Cathepsin B on the other hand is inactivated by this reagent, as described earlier as well as by other peptidyl diazomethyl ketones. It appears from initial studies that a phenylalanyl residue in the penultimate position of the inhibitor is favorable for effectiveness. Benzyloxycarbonyl-Phe-AlaCHN2 emerges from this work as a powerful, relatively soluble inactivator of bovine spleen cathepsin B with Ki = 1.7 × 10-6M. © 1979.