关键词: 化学修饰, 手性伯醇, 对映体选择性, 分子动力学模拟, 洋葱假单胞菌脂肪酶

Abstract: In our work，ester hydrolysis of chiral primary alcohols was adopted as model reaction. The results showed that those chiral primary alcohols with non-acyloxy oxygen atom were able to be resolved by Pseudomonas cepacia lipase (PcL) with a relatively high enantioselectivity，but those without the extra oxygen did not. Investigation by chemical modification of PcL by N-acetylimidazole indicated enantioselectivity towards primary alcohol with the non-acyloxy oxygen decreased significantly，but those without retained almost the same low value. Protein mass spectrometry analysis suggested that Tyr29 in PcL had a significant effect on selectivity inside the active center. Further investigation by molecular simulation indicated that phenolic hydroxyl hydrogen atom in PcL’s Tyr29 was able to serve as an extra hydrogen bond donor，and could form a hydrogen bond with the extra oxygen of primary alcohol. To a large extent，whether the substrate molecule could form a hydrogen bond with Tyr29 of PcL decided the lipase’s enantioselectivity. The mechanism of enantioselectivity towards chiral primary alcohols via study of chemical modification of PcL was proposed.

Key words: chemical modification, chiral primary alcohol, enantioselectivity, molecular dynamics, Pseudomonas cepacia lipase