A synthetic peptide inhibitor that irreversibly inhibits caspase-3 and related protease/caspase activity and blocks apoptosis. DEVD is the specific recognition sequence found in poly (ADP-ribose) polymerase (PARP). The inhibitor is designed as a methyl ester to facilitate cell permeability. (CAUTION: If the intended use is on purified or recombinant enzymes, esterase should be added to generate free carboxyl groups).