L-Leucinamide, N-acetyl-L-leucyl-N-[(1S)-4-[(aminoiminomethyl)amino]-1-formylbutyl]-, hydrochloride (1:1)

Leupeptin is a naturally occurring protease inhibitor that can inhibit cysteine, serine and threonine peptidases. Leupeptin is an organic compound produced by actinomycetes. Leupeptin inhibits serine proteinases (trypsin (Ki=3.5 nM), plasmin (Ki= 3.4 nM), porcine kallikrein), and cysteine proteinases (papain, cathepsin B (Ki = 4.1 nM), endoproteinase Lys-C). It does not inhibit α-chymotrypsin or thrombin. Leupeptin is a competitive transition state inhibitor and its inhibition may be relieved by an excess of substrate.