乙醇溶液中Tweens对猪胰脂酶的修饰作用

采用Tween系列表面活性剂在乙醇-水溶液体系中对猪胰脂酶进行修饰,以它们催化酯交换的交换量为指标评价修饰的效果,并且对修饰酶与未修饰酶的热稳定性进行了研究。结果表明:40℃下30 min即可完成Tweens对猪胰脂酶的修饰,但不同Tween的最佳条件并不相同。Tween 20修饰脂肪酶的最佳条件是无水乙醇与水的比例为1∶2(v/v),Tween 20用量为5%;Tween 40和Tween 65修饰猪胰脂酶的最佳条件是无水乙醇与水的比例为1∶2(v/v),用量均为15%;Tween 60修饰猪胰脂酶的最佳条件为无水乙醇与水的比例为1∶2(v/v),用量为20%;Tween 80修饰脂肪酶的最佳条件是无水乙醇与水的比例为1∶3(v/v),用量为5%;Tween 85修饰脂肪酶的最佳条件是无水乙醇与水的比例为1∶3(v/v),用量为15%。修饰后酶的热稳定性实验研究表明,在40～80℃间,修饰酶的催化反活性都高于未修饰酶。Tweens修饰猪胰脂酶能有效提高酶的活性及其热稳定性。

Modification of Porcine Pancreas Lipase by Tweens in Ethanol Solution

The porcine pancreas lipase(PPLipase) was modified by Tweens in the ethanol-water solution in this paper,the efficiency of the modification of the PPLipase was determined by incorporation of interesterification of oils catalyzed by them,and the thermal stability of the modified PPLipases and the original PPLipase was also studied.The results indicate that the modification could be finished in 30min at 40℃,however the optimum conditions for different Tweens were not the same.For Tween20,the optimum conditions were the ratio of ethanol to water 1∶2(v/v),the amount of Span20 5%.For Tween40 and Tween65,the optimum conditions were the ratio of ethanol to water 1∶2(v/v),the amount of them 1520%.For Tween65,the optimum conditions were the ratio of ethanol to water 1∶2(v/v),the amount of Tween 20%.For Tween80,the optimum conditions were the ratio of ethanol to water 1∶3(v/v),the amount of Tween80 5%.For Tween85,the optimum conditions were the ratio of ethanol to water 1∶3(v/v),the amount of Tween85 15%.The catalytic activity of the modified PPLipase was higher than that of the original PPLipase in the range of 40℃ to 80℃ and the modified lipases showed the better catalytic activity in the range of 40~70℃.The modification of PPLipase by Tweens could improve the catalytic activity and thermal stability dramatically.