From Nocardia rubraActivity: 5,000 to 50,000 units/ml. Supplied in 50% glycerol containing 10 mM Tris-HCl pH 7.4, 0.1 mM EDTA, 50 mM KCl, 1.0 mM dithiothreitol, 200 mg/ml BSA.Ref.: Recognition and cleavage site from: Schildkraut, I. and Greenough, L. unpublished observations.