反应条件对脂肪酶酯化活性和对映选择性的影响

Effect of Reaction Parameters on Reactivity and Enantioselectivity of Lipase-catalyzed Esterification

分别测定了2-萘基丙酸类药物萘普生R-、S-对映体在有机溶剂中的酶促酯化反应初速度，并研究了反应温度、酰基受体和有机溶剂等反应条件对脂肪酶的反应活性和对映选择性的影响。在一定范围内，酶反应活性随温度升高而增加，温度过高易使酶失活；酶选择性则随温度升高而下降；反应温度以35～40℃为佳。在疏水性强的溶剂中，酶反应活性较大；酶的选择性则以异辛烷、苯、甲苯等为溶剂时较好。合适的混合溶剂系统能使酶表现出比在单一溶剂中更好的活性和选择性；这与外消旋萘普生的实际酶促拆分结果是一致的。

The initial reaction rates of S- and R-naproxen esterification catalyzed by lipase wereseparately measured to characterize the reactivity and enantioselectivity of the enzyme and the effect ofreaction parameters including temperature, acyl receptor and solvent have been investigated.Increasing temperature, reactivity increased while enantioselectivity decreased,with an optimumbetween 35-40℃. The enzyme showed higher activity in hydrophobic solvents (with high LogP value)such as isooctane, cyclohexane. Higher enantioselectivity was obtained in isooctane, benzene, andtoluene. Higher reactivity and enantioselectivity were observed in an appropriate mixed solvent system(benzene + cyclohexne) than in the single solvent, which is consistent with the result of enzymaticresolution of racendc naproxen.