【摘要】 地衣芽孢杆菌JF UN12 2的发酵液 ,以硫酸铵分段盐析得粗酶 ,再经DEAE SephadexA 5 0吸附色素、CM SephadexC 5 0离子交换及SephadexG 75柱层析等步骤获得电泳纯的碱性蛋白酶。SDS PAGE测得其分子量为 31.6KDa。以酪蛋白为底物时 ,酶的Km为 5 .2 6 μg/mL ,Vm为2 0 .8μg/min。酶的最适 pH为 9.0 ,最适温度为 5 5℃ ,pH 5～ 11,5 5℃以下酶较稳定 ,对 1mol/LH2 O2 具有一定的耐氧化性。PMSF对酶抑制 ,二硫苏糖醇 (DTT)有保护作用 ,钙离子、EDTA、SDS、尿素等对酶无明显影响更多还原

【Abstract】 An alkaline protease was purified from the culture of Bacillus licheniformis JF UN122 by ammonium sulfate precipitation followed by DEAE Sephadex A 50 chromatography, CM Sephadex C 50 chromatography and Sephadex G 75 chromatography. The purified proteinase was demonstrated to be electrophoretic homogeneity by SDS PAGE , with a molecular weight of 31.6kDa . The Km for casein was 5.26 μg/mL and Vm was 20.8 μg/min . The optimum pH and temperature for hydrolysis of casein were 9.0 and 55℃, respectively . The enzyme was stable up to 55℃, within the pH range of 5～11. PMSF nearly inhibited its activity while other ions and reagents such as calcium , EDTA , urea and SDS had no notable effects on the activity of the protease . In addition , it could resist 1mol/L H 2O 2 and be protected by dithiothreitol(DTT).更多还原