A synthetic peptide that irreversibly inhibits activity of caspase family proteases and blocks apoptosis. The inhibitor is designed as a methyl ester to facilitate cell permeability. The product can be used in both in vitro and in vivo studies. 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).