Development of Surfactant Modified Enzymes That Show High Activity in Organic Media.

在过去的十年里，在非水介质中利用酶已被认为是最简单但最有前途的技术之一，用于各种疏水酸和酒精的对映选择性转化。酶的高对映体选择性是一个吸引人的特征，特别是在生产光学活性化合物方面。在我们最近的研究中，发现了一种表面活性剂-酶复合体在非水介质中具有催化活性。利用W/O乳状液制备表面活性剂-酶复合体的方法非常简单，不需要复杂的技术，在无水有机溶剂(如异辛烷和甲苯)中，经该方法修饰的蛋白酶表现出很高的活性。在本研究中，在无水有机溶剂中进行了表面活性物质-蛋白酶复合体催化的多肽合成。讨论了酶的来源、加水、有机溶剂、共溶剂以及底物种类对酶活力的影响。与天然脂肪酶相比，表面活性物质-酶复合体在高温下具有较好的热稳定性，并表现出较高的储存稳定性。此外，该脂肪酶复合体具有较高的储存稳定性。这种修饰方法将使我们能够利用许多在有机介质中没有表现出酶活性的酶作为新的生物催化剂。

The utilization of enzymes in nonaqueous media has been probed to be one of the simplest but the most promising techniques for the enantioselective conversion of various hydrophobic acids and alcohol in the last decade. The high enantioselectivity of enzymes is an attractive feature, in particular, for producing optically active compounds. In our recent investigation, a surfactant-enzyme complex was found to be catalytically active in nonaqueous media. The preparation method of surfactant-enzyme complexes utilizing W/O emulsions is very simple and does not require complicating techniques.Proteases modified by this preparation method showed high activity in anhydrous organic solvents such as isooctane and toluene. In the present study, a peptide synthesis catalyzed by surfactant-protease complex is conducted in anhydrous organic solvents. The effects of origin of proteases, addition of water, organic solvents, cosolvents were discusses ad well as that of the kind of substrates on the enzymatic activity. The surfactant-protease complexes were thermostable at high temperature, and showed a high storage stability.The surfactant-lipase complexes were also thermostable at high temperature compared to the native lipase. Furthermore, the lipase complex showed a high storage stability. This modification method will enable us to utilize a lot of enzymes as new biocatalysts which had not shown enzymatic activity in organic media.