Purity >97% by HPLC. Potent, competitive and reversible cysteine, serine and threonine protease inhibitor. Inhibits calpain, kallikrein, trypsin, plasmin, papain and cathepsin B. Does not inhibit pepsin, elastase, renin, cathepsins A and D, thrombin or alpha-chymotrypsin. Used to protect against hearing loss caused by acoustic overstimulation or the ototoxic antibiotic gentamicin. Shown to inhibit activation-induced programmed cell death. Antioxidant and anti-inflammatory agent. Widely used as a protein purification tool to prevent proteases present in tissue samples from degrading the protein of interest.