LIPASE-CATALYZED TRANSESTERIFICATION IN ORGANIC-SOLVENT - EFFECTS OF WATER AND SOLVENT, THERMAL-STABILITY AND SOME APPLICATIONS
LIPASE-CATALYZED TRANSESTERIFICATION IN ORGANIC-SOLVENT - EFFECTS OF WATER AND SOLVENT, THERMAL-STABILITY AND SOME APPLICATIONS
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DOI：
10.1016/0168-1656(90)90004-u
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发表时间：
1990-05-01
影响因子：
4.1
通讯作者：
YAMASHINA, T
中科院分区：
文献类型：
--
作者：
HIRATA, H;HIGUCHI, K;YAMASHINA, T
研究了脂肪酶催化三丁酸甘油酯与不同醇在非均相体系中的酯交换反应。存在最佳水含量（H2O）op，其中酶显示最大活性，并且其值受酶和底物的水合、酶的凝结、溶剂的性质（水混溶性-不混溶性）以及酶和底物溶液之间的水平衡的影响。在限水环境中，假单胞菌脂肪酶非常稳定，并显示出酶活性，其中一部分通过补充水分恢复。这表明热共沸脱水在有机溶剂中酶的热失活中起作用。酶的催化活性主要取决于溶剂的极性、结构以及溶剂对酶的脱水作用。带有直链的脂肪族伯醇的反应性取决于溶剂的性质，并且不同于水溶液中相应的丁酸烷基酯的酶促水解。通过与2-烷醇的酯交换反应，确定了一种光学活性酯的合成策略和醇的光学拆分。
The lipase-catalyzed transesterification of tributyrin with various alcohols in a heterogeneous system was investigated using powdered enzyme suspended in numerous organic solvents. There is an optimum water content, (H2O)op, where the enzyme shows the maximal activity and its value is affected by the hydration of the enzyme and the substrate, coagulation of the enzyme, the nature (water-miscible-immiscible) of the solvent and the water equilibrium between the enzyme and the substrate solution. In a water-restricted environment, Pseudomonas lipases were very stable and showed enzymatic activities, parts of which were restored by water supplementation. This suggests that a thermally azeotropic dehydration plays a part in the thermoinactivation of the enzyme in organic solvents. The catalytic activity of enzyme was predominantly determined by the polarity and the structure of the solvent, and the dehydration of the enzyme by the solvent. The reactivity of an aliphatic primary alcohol bearing a straight chain was dependent on the nature of the solvent and differed from that for enzymatic hydrolysis of the corresponding alkyl butyrate in aqueous solution. Investigations of the transesterification with 2-alkanol confirmed a synthetic strategy of the optically active esters and optical resolution of the alcohol.