1.13.11.6 | bovine kidney homogenized in 0.1 M potassium dihydrogen phosphate buffer with 20% glycerol and 3 mM 2-mercaptoethanol, pH 7.4, centrifuged, protein fraction of supernatant that precipitates from 34-62% saturated (NH4)2SO4 is resuspended in 5 mM potassium dihydrogen phosphate buffer with 20% glycerol and 3 mM 2-mercaptoethanol, pH 7.4, dialyzed against same buffer containing protease inhibitor PMSF (0.1 mM), applied to DEAE Sephadex A-50 column, fractions with enzyme activity pooled and concentrated by precipitation with 80%-saturated (NH4)2SO4, dialyzed against 10 mM Tris-HCl with 20% glycerol and 3 mM 2-mercaptoethanol, pH 7.4, applied to Blue-Sepharose CL-4B column, concentration of active fractions by ultrafiltration through YM-10 membrane |