MOLECULAR PROPERTIES OF PEP CARBOXYLASE REVELANT TO ITS ALLOSTERIC REGULATION

磷酸烯醇式丙酮酸(PEP)羧基酶因其核心功能而备受关注。 在CAM和C4植物光合代谢中的作用就像是 对于主要代谢途径中的一个关键酶来说， 酶是高度受调节的，一个基本的调节元件似乎是 是由磷酸化激活剂引起的激活的相互作用 葡萄糖、6-磷酸和AMP以及苹果酸和三磷酸腺苷的抑制作用。 这项研究的总体目标是阐明分子的各个方面。 效应器，特别是AMP和AMP等激活剂的过程 葡萄糖6-磷酸，调节青海牡蛎PEP羧化酶和 其他消息来源。这项研究将探索激活剂的结合部位(S) 以及通过使用光亲和标记的抑制剂。建议数 研究还将测试激活的分子机制，鉴于 最近提出了一个新的假说。具体目标 包括估计激活剂结合位点的数量和 激活剂的离解常数，决定所有 激活剂共享一个共同的结合部位，比较AMP和ATP结合 位点，识别激活剂结合位点上的肽序列，以及 检测激活剂去磷酸化在激活过程中的作用。 预计结果将提供有关如何以及在哪里进行的分子信息。 激活剂对酶产生影响。此信息将 更深入地了解以下内容的结构-功能关系 特定的酶，更广泛地说，进入新陈代谢过程 在酶水平上的调节。

Phosphoenolpyruvate (PEP) carboxylase is of interest because of its central role in the photosynthetic metabolism of CAM and C4 plants. As would be expected for a key enzyme in a major metabolic pathway, the activity of the enzyme is highly regulated, and a fundamental regulatory element appears to be the interplay of the activation caused by phosphorylated activators such as glucose 6-phosphate and AMP and the inhibition caused by malate and ATP. The overall goal of this research is to elucidate various molecular aspects of the process by which effectors, particularly activators such as AMP and glucose 6-phosphate, regulate PEP carboxylase from Crassula argentea and other sources. The research will probe the binding site(s) of activators and inhibitors through the use of photoaffinity labels. The proposed research will also test the molecular mechanism of activation, in light of a novel hypothesis that has recently been proposed. The specific aims include estimating the number of activator binding sites and the dissociation constants for the activators, determining whether all activators share a common binding site, comparing the AMP and ATP binding sites, identifying the peptide sequence at the activator binding site, and testing the role of activator dephosphorylation in the activation process. The results are expected to provide molecular information on how and where activators exert their influence on the enzyme. This information will provide greater insight into the structure-function relationships of this specific enzyme and, more generally, into the process of metabolic regulation at the enzyme level.