ENZYMIC SYNTHESIS OF BIOACTIVE AGENTS IN ORGANIC MEDIA

作为最近工作的结果，已经清楚的是，许多酶可以 在纯有机溶剂而不是水中起催化剂的作用， 当置于这种极端和非自然的环境中时， 非凡的新特性 建议的总体目标 研究是探索新的合成机会， 在有机溶剂中的酶催化，特别是用于开发 不对称和其他选择性转换， 用于生产生物医学相关化合物。 我们 在前一个授予期间发现，溶剂显着 影响酶的选择性（包括对映选择性， 化学选择性和区域选择性）将在机械上 研究了 为此，我们将进行动力学，计算机模拟， 结构-功能关系实验，考察溶剂 酶构象动力学的依赖性似乎发挥了作用， 在有机溶剂中酶的作用至关重要。 蛋白质动力学将 使用2 H和二维1H NMR光谱进行研究。 的 最终目标将是详细阐述物理化学原理， 将解释和预测立体化学的依赖， 非水介质中酶促过程的反应途径，例如，的 脂肪酶催化的酯交换和氨解反应， 蛋白酶，对溶剂的基本特性。 的 通过改变溶剂随意控制酶选择性的能力 将提供一种迄今为止无法获得的调节酶活性的方法， 性质（“溶剂工程”），这将是一个补充 替代蛋白质工程方法。 也会导致 在酶的选择性方面的深刻的，合理的改进 转化，如外消旋体的拆分和位点特异性 多官能有机化合物的改性。

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.