Leupeptin is a modified tripeptide reversible protease inhibitor of trypsin-like proteases and some cysteine proteases including endoproteinase Lys-C, kallikrein, papain, thrombin, cathepsin B, cathepsins H and L, trypsin, calpain, trypsin8 and plasmin. Effective concentration is typically 10-100 uM. Little to no inhibition is seen against pepsin, cathepsins A and D and alpha-chymotrypsin. When adjusted for molarity, all three salt forms are equally effective; however, the hydrochloride salt is usually less invasive in biological settings.

• Presentation: White Powder
• Soluble in water (50 mg/mL-clear, faint yellow solution).

Leupeptin is a Inhibitor for trypsin, plasmin, papain, and cathepsin B.

Inhibitor of serine and cysteine proteases. Inhibits plasmin, trypsin, papain, calpain, and cathepsin B. Does not inhibit pepsin, cathepsins A and D, thrombin, or α-chymotrypsin. There have been numerous studies using leupeptin to protect against hearing loss caused by acoustic overstimulation or the ototoxic antibiotic gentamicin. (Loss of cochlear hair cells is believed to be mediated by calpain.)

Leupeptin gives multiple peaks on HPLC due to equilibria among three forms in solution. Purity determined using three main peaks. Majority of contaminating peptide is racemized leupeptin.