Not available outside of the UK & Ireland.

Analysis Note

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.

Biochem/physiol Actions

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. Effective concentration 10-100 µM. 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.)

Other Notes

Inhibitor of trypsin, plasmin, papain and cathepsin B

Unit Definition

1 U corresponds to the amount of inhibitor which reduces the trypsin activity by 1 BAEE-U. (1 BAEE-U is the amount of enzyme which increases the absorbance at 253 nm by 0.001 per minute at pH 7.6 and 25 °C; BAEE, Cat. No. 12880, as substrate)