Liquid. In 20 mM sodium acetate buffer, 1 mM EDTA, pH 5.0. AVOID FREEZE/THAW CYCLES. Native cathepsin B from bovine spleen, purified by affinity chromatography. Cathepsin B, one of the most investigated lysosomal cysteine proteinases, is widely distributed in a variety of tissues. The enzyme exists in a two-polypeptide chain form consisting of an H-chain of 22 - 23 kDa and an L-chain of 5 kDa. Cathepsin B is shown to facilitate tumor invasion by dissolving extracellular barriers. Specific activity: ≥10 units/mg protein. One unit is defined as the amount of enzyme that will hydrolyze 1.0 µmol of Z-RR-pNA per min at 37°C, pH 6.0. Purity: single band by non-reducing SDS-PAGE. pH optimum 3.0 - 4.0. EC 3.4.22.1, CAS 9047-22-7.

Ref.: Katunuma, N., et al. 1998. Adv. Enzyme Regul. 38, 235. Aisa, M.C., et al. 1996. Biochim. Biophys. Acta 1290, 29. Everts, V., et al. 1996. Histochem. J. 28, 229.