Leupeptin is a competitive protease inhibitor produced by actinomycetes. Leupeptin can inhibit cysteine, serine and threonine peptidases. Leupeptin inhibits serine proteinases (trypsin (Ki=3.5 nM), plasmin (Ki= 3.4 nM), porcine kallikrein), and cysteine p
K-252c is a staurosporine analog isolated from Nocardiopsis sp. and is a cell-permeable PKC inhibitor (IC50: 2.45 μM). K-252c also inhibits β-lactamase, chymotrypsin, and malate dehydrogenase. K-252c causes apoptosis in human chronic myelogenous leukemia cancer cells.