Coenzyme A Analogs as Probes of Enzymatic Reactions

9722936 Drueckhammer本项目的目的是使用合成的CoA类似物作为探针研究辅酶A（CoA）酯利用酶的催化机制。 柠檬酸合成酶反应的机理和中间产物的性质将是今后的研究方向。 将制备和研究另外的乙酰辅酶A烯醇和烯醇化物类似物作为柠檬酸合酶的探针，包括设计用于允许直接观察稳定的酶-烯醇或酶-烯醇化物复合物的类似物。 将使用新制备的乙酰辅酶A的亲电酮类似物对乙酰辅酶A依赖性乙酰转移酶的机制进行进一步研究。 这些研究可能会提供新的见解的酶的中间体和酶的过渡态复合物的结构和乙酰转移酶稳定这些物种的手段。 将制备CoA的类似物，其具有改变的最接近硫醇基团的酰胺键。这些类似物将用于初步研究远离CoA巯基的官能团在酶促反应中稳定和不稳定基态和过渡态复合物中的作用。 酶催化几乎所有生物体中发生的生化反应，据估计，约4%的酶在其反应中需要辅酶A（CoA）或CoA的衍生物。 这些包括具有工业、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提供新的见解，它们故障的基础，以及它们的功能可能被调节或改变的方法。

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.