A synthetic peptide that irreversibly inhibits FLICE and related protease/caspase activity and blocks apoptosis. IETD is the specific recognition sequence found in CPP32 proenzyme. 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.)