60525-17-9 Benzyloxycarbonylphenylalanyl-alanine chloromethyl ketone Boc-phe-ala-cmk Carbamic acid, (2-((3-chloro-1-methyl-2-oxopropyl)amino)-2-oxo-1-(phenylmethyl)ethyl)-, phenylmethyl ester, (S-(R*,R*))- ZPACK