有机介质中酶催化的基本原理

酶在有机溶剂中催化作用的研究日益受到重视,其应用范围也越来越广.本文就有机介质中酶催化的基本原理进行了讨论,包括酶的结构和催化机理,以及溶剂和水对酶的结构和催化功能的影响.同时,本文归纳出提高酶活性的一系列方法,其中不少方法简便易行,能使酶活性提高10²-10⁵倍.

Fundamentals of Biocatalysis in Organic Solvents

Nonaqueous enzymology has attracted more and more interests from researchers and industry because of the unique properties provided by enzymes in nonaqueous environments. Supported by an exponential growth of the literature, this rapidly developing research area has made tremendous progress in recent years in gaining an improved fundamental understanding of enzyme function and activation in organic media. In such a non-conventional milieu, the enzyme maintains its structural and mechanistic integrity. The role of water and solvents on enzyme function has been discussed in detail, such as the effects of water on enzyme activity and protein mobility, the effects of solvent on the water associated with the enzyme, on enzyme's active site and protein dynamics and conformation, on substrates and products, and on the enzymatic activation energy. A series of methods and techniques for activating enzymes in organic solvents have been summarized, such as to overcome the limitations in diffusion and accessibility, to optimize the pH situation, to minimize the effect of solvents on activation energy, to enhance the conformational mobility of the enzyme, and to prevent enzyme denaturation during dehydration by lyophilizing enzymes in the presence of a selection of organic or inorganic excipients (e.g. nonbuffer salts or macrocycles). These techniques are quite simple and scalable, and can promote a wide range of enzyme activation (up to 10~5-fold) through different mechanisms. All these will undoubtedly help us to effectively design high-activity enzyme preparations suitable for use in organic solvents and to broaden the applications of nonaqueous enzymology to a greater extent.