【摘要】 巨大芽孢杆菌青霉素G酰化酶共价结合在新型环氧-氨基型载体ZH-HA上,通过对酶浓度、固定化时间、pH以及缓冲液浓度等条件的考察,确定了最优固定化条件:50 mg比活力6000U/g的巨大芽孢杆菌青霉素G酰化酶蛋白和1g ZH-HA悬浮于pH9.0 1 mol/L磷酸缓冲液,室温搅拌6 h,制得固定化巨大芽孢杆菌青霉素G酰化酶,活力2126 U/g湿载体,活力回收率7.67%。比较研究了固定化酶与原酶性质,原酶最适温度45℃,最适pH为8.0。固定化酶则分别是50℃和9.0,分别比溶液酶偏移5℃、1.0个pH单位。经过40批连续水解青霉素G钾盐,固定化巨大芽孢杆菌青霉素酰化酶仍保持80%的活力,显示出良好的工作稳定性。更多还原

【Abstract】 New epoxy-type support ZH-HA was employed to immobilized Bacillus megaterium penicillin G acylase.The immobilization conditions including the ratio of the enzyme to the support,pH,and buffer concentration were studied and the optimized immobilization conditions were 50 mg protein per g support,6 h at room temperature,pH9.0 and 1mol/L phosphate buffer.The enzymatic properties of immobilized Bacillus megaterium penicillin G acylase were investigated and compared with those of free enzyme.The optimal temperature and pH of immobilized enzyme were 50℃and 9.0 respectively,exhibiting an increase of 5℃ and 1.0 pH unit compared with free enzyme.The immobilized enzyme also possessed an improved pH and thermal stability.After hydrolyzing penicillin G 40 times in a batch reactor,the immobilized Bacillus megaterium penicillin G acylase showed a good operational stability.更多还原