功能化离子液体化学修饰猪胰脂肪酶的催化性能

摘要

Porcine pancreatic lipase ( PPL ) was modified with functionalized ionic liquids ([HOOCMMIm][Cl],and [HOOCEMIm][Cl],[HOOCBMIm][Cl])�Activity in buffer and organic solvents,thermostability,and ultraviolet spectrum of the modified PPL were compared with those of the unmodified PPL in the triacetin hydrolysis reaction�The results showed that modified enzymes were more tolerant to temperature and low pH changes and had both higher activity and stability�Functionalized ionic liquids modification enhanced thermal stability of PPL�Enzymes contained 100% activity of PPL in high concentration of methanol and N,N-dimethylformamide( DMF) after modification�After PPL was modified by functionalized ionic liquids,red shift of PPL characteristic ultraviolet peak and absorbance increase occurred due to changes of lipase microenvironment�%选取氯化1羧甲基3甲基咪唑、氯化1羧甲基3乙基咪唑、氯化1羧甲基3丁基咪唑3种离子液体对猪胰脂肪酶（ PPL）进行化学修饰，得到3种修饰的脂肪酶分别命名为PPL M、PPL E、PPL B。以三乙酸甘油酯水解为模型反应，考察离子液体修饰前后PPL的活力、热稳定性、耐有机溶剂性等酶学性质，并通过紫外光谱研究修饰对PPL空间结构的影响。结果表明：修饰后PPL的活力明显提高，对温度和pH的敏感度降低。修饰酶的热稳定性明显提高，在高浓度的甲醇及N，N 二甲基甲酰胺（ DMF）中仍能保持游离酶活力的100％。修饰后酶的特征吸收峰发生红移，吸收强度增强，修饰后酶的微环境发生了改变。