 The suggested concentration is 1-10 μM (0.5-5 μg/ml).Leupeptin is an organic compound produced by actinomycetes, which inhibits serine, cysteine and threonine proteases.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).