ENZYMIC SYNTHESIS OF BIOACTIVE AGENTS IN ORGANIC MEDIA

最近的研究结果表明，许多酶可以 在纯净的有机溶剂中起到催化剂的作用，而不是水 当被放置在这种极端和非自然的环境中时，酶表现出 值得注意的新特性。建议的总体目标是 研究是探索新的合成机会，由 酶在有机溶剂中的催化作用，特别是对于发展 不对称的和选择性的转换，以及它们的 在生物医学相关化合物的生产中的应用。我们的 在上一次授权期内发现该溶剂明显 影响酶的选择性(包括对映体选择性， 化学选择性和区域选择性)将是机械性的 调查过了。为此，我们将进行动力学、计算机模拟， 并进行了构效关系实验和溶剂考察 对酶构象动力学的依赖性，这些酶似乎发挥着 在有机溶剂中的酶作用中起关键作用。蛋白质动力学将 用~2H和二维~1H核磁共振波谱进行研究。这个 最终目标将是阐述一种物理化学原理， 将解释和预测立体化学和 酶过程在非水介质中的反应路径，例如 脂肪酶催化的酯交换和氨解反应 蛋白水解酶，对溶剂的基本特性。这个 能够通过改变溶剂来随意控制酶的选择性 将为酶的调节提供一种迄今不可用的手段 性质(“溶剂工程”)，这将是一个补充 蛋白质工程方法的替代方案。它还将导致 深刻、合理地提高了酶的选择性 转化，如外消旋体的拆分和特定部位的转化 多官能团有机化合物的改性。

As a result of recent work, it has become clear that many enzymes can function as catalysts in neat organic solvents instead of water, and that when placed in this extreme and unnatural environment enzymes exhibit remarkable new properties. The overall objective of the proposed research is to explore novel synthetic opportunities afforded by enzymatic catalysis in organic solvents, particularly for the development of asymmetric and otherwise selective transformations and for their utilization in the production of biomedically relevant compounds. Our discovery during the preceding grant period that the solvent markedly affects enzyme selectivity (including enantioselectivity, chemoselectivity, and regioselectivity) will be mechanistically investigated. To this end, we will pursue kinetic, computer simulations, and structure-function relationship experiments and examine the solvent dependence of enzyme conformational dynamics which appear to play a crucial role in enzyme action in organic solvents. Protein dynamics will be studied using 2H and two-dimensional 1H NMR spectroscopies. The ultimate goal will be to elaborate a physico-chemical rationale which will explain and predict the dependence of the stereochemistry and reaction pathways of enzymatic processes in non-aqueous media, e.g., of transesterification and aminolysis reactions catalyzed by lipases and proteases, on the fundamental characteristics of the solvent. The ability to control at will enzyme selectivity by changing the solvent will provide a heretofore unavailable means of regulation of enzymatic properties ("solvent engineering"), which will be a complementary alternative to protein engineering approaches. It will also lead to profound, rational improvements in the selectivity of enzymatic conversions, such as resolution of racemates and site-specific modification of polyfunctional organic compounds.