An irreversible protease inhibitor; irreversibly inhibits recombinant caspase-3, cathepsin B, cathepsin L, cathepsin V, cathepsin F, and cathepsin S in enzyme assays; improves endotoxin-induced myocardial dysfunction and reduces caspase-1,-3, and -8 activation and apoptosis in a rat model of endotoxin-induced myocardial dysfunction and heart apoptosis at 3 mg/kg,