疏水性脯氨酸离子液体化学修饰提升猪胰脂肪酶催化性能

A series of proline ionic liquids possessing hydrophobic alkyl of different lengths were used to modify porcine pancreatic lipase(PPL) for improving its activity and stability. The results indicated that the enzymatic properties of all modified lipases were enhanced and [ProC₈][H₂PO₄]-PPL showed the best catalytic performance. The optimal catalytic activity of hydrolyzing olive oil was 2.7 times compared with the native lipase, and the residual enzyme activity was 5.0 times after being stored at 50 ℃ for 2 h. The catalytic efficiency K_cat.K_m^-1 was 4.4 times that of the native lipase, and the enantioselectivity of α-phenylethanol esterification increased by 1.6 times. The spectroscopic characterization revealed the changes of secondary structure and fluorophore microenvironment of PPL, which were associated with the increase of activity and stability of the modified enzyme. Compared with results previously reported, the novel proline ionic liquid provides a more effective improvement in the catalytic performance of lipase.