Coenzyme A Analogs as Probes of Enzymatic Reactions

本项目的目的是研究辅酶A （CoA）酯的催化机制——利用酶，以人工合成的辅酶A类似物为探针。进一步的研究将针对柠檬酸合酶的反应机理和中间体的性质进行探讨。额外的乙酰辅酶a烯醇和烯酸酯类似物将被制备和研究作为柠檬酸合成酶的探针，包括设计用于直接观察稳定的酶-烯醇或酶-烯酸酯复合物的类似物。我们将利用新制备的乙酰辅酶a的亲电酮类似物进一步研究乙酰辅酶a依赖性乙酰转移酶的作用机制。这些研究可能为酶-中间体和酶-过渡态复合物的结构以及乙酰转移酶稳定这些物种的手段提供新的见解。制备辅酶a类似物时，最靠近巯基的酰胺键被改变。这些类似物将用于初步研究远离辅酶a巯基的官能团在酶促反应中基态和过渡态络合物的稳定和不稳定中的作用。酶几乎催化了生物体中发生的所有生化反应，据估计，大约4%的酶在其反应中需要辅酶A （CoA）或CoA的衍生物。这些酶包括具有工业、生物技术和生物医学重要性的酶。该项目旨在了解这些酶的功能所涉及的潜在化学。这项工作将为酶如何工作、酶功能失调的基础以及酶的功能可能被调节或改变的方式提供新的见解。

9722936 Drueckhammer The objective of this project is to study the mechanisms of catalysis by Coenzyme A (CoA) ester-utilizing enzymes using synthetic CoA analogs as probes. Further studies will be directed at investigation of the mechanism and the nature of the intermediate in the reaction of citrate synthase. Additional acetyl-CoA enol and enolate analogs will be prepared and studied as probes of citrate synthase, including analogs designed to permit direct observation of a stable enzyme-enol or enzyme-enolate complex. Further studies will be conducted on the mechanism of acetyl-CoA dependent acetyltransferases using newly prepared electrophilic ketone analogs of acetyl-CoA. These studies may provide new insights into the structure of the enzyme-intermediate and enzyme-transition state complexes and the means by which the acetyltransferases stabilize these species. Analogs of CoA will be prepared having the amide bond nearest the thiol group altered. These analogs will be used in initial investigations of the role of functional groups remote from the thiol group of CoA in stabilization and destabilization of ground state and transition state complexes in enzymatic reactions. Enzymes catalyze almost all of the biochemical reactions that occur in living organisms and it is estimated that about 4% of all enzymes require coenzyme A (CoA) or a derivative of CoA in their reactions. These include enzymes of industrial, biotechnological, and biomedical importance. This project is directed at understanding the underlying chemistry involved in the function of these enzymes. This work will provide new insights into how enzymes work, the basis for their malfunction, and the means by which their function may be modulated or altered.