STUCTURE FUNCTION AND REGULATION OF NADPH CYTOCHROME P450 OXIDOREDUCTASE

从生化意义上讲，混合功能的氧化酶系统代表了 人类与环境之间的第一道防线。这个系统是 负责他们排毒的早期代谢步骤 外源生物以及某些化学物质的代谢活化 致癌物质。因此，细胞对外来化合物的反应和 细胞的最终命运取决于这些键的活性水平 酵素。 这项建议是我们正在进行的研究的延伸， 结构。NADPH-细胞色素P450的功能及其调控 氧化还原酶(P450R)和细胞色素3A家族。四个主要领域将 在下一个授权期内解决的问题。第一个将检查那些 还原酶分子的结构特征，这是负责 维持黄素结构域的最佳比对和完整性。三 将对具体地区进行分析。这些是相互连接的Flain 结构域，对结构很重要的羧基末端区域 和FAD/NADPH结合域的功能特性，是端口 电子从NADPH进入的位置，以及FMN附近的铰链区 域。第二个领域将重点确定表彰地点(S)上 P450R表面对细胞色素的选择性结合 P450和其他蛋白质底物，如细胞色素b5和血红素 加氧酶。第三，P450R和CYP3A23基因的调节将是 为了更好地了解控制疾病的因素进行了调查 这些酶的细胞水平。第四，P450R的生物学作用 将通过研究发育和组织特异性进行评估 应用原位杂交和免疫组织化学技术检测HSP70的表达 在P450R基因座上产生一个零等位基因的小鼠品系。

In a biochemical sense, the mixed-function oxidase system represents the first line of defence between man and his environment. This system is responsible for the early metabolic steps in they detoxification of xenobiotics as well as the metabolic activation of certain chemical carcinogens. Hence, the response of the cell to foreign compounds and the eventual fate of the cell depends upon the activity level of these key enzymes. This proposal is an extension of our ongoing studies dealing with the structure. function, and regulation of NADPH-cytochrome P450 oxidoreductase (P450R) and the cytochrome 3A family. Four major areas will be addressed during the next granting period. The first will examine those structural features of the reductase molecule that are responsible for maintaining optimal alignment and integrity of the flavin domains. Three specific regions will be analyzed. These are the interconnecting flavin domain, the carboxyl terminal region that is important for the structural and functional character of the FAD/NADPH binding domains and is the port of entry for electrons from NADPH, and the hinge region close to the FMN domain. The second area will focus on identify the recognition site(s) on the surface of P450R responsible for the selective binding of cytochrome P450 and other protein substrates such as cytochrome b5 and heme oxygenase. Third, the regulation of the P450R and CYP3A23 genes will be investigated in order to better understand the factors controlling the cellular levels of these enzymes. Fourth, the biological role of P450R will be evaluated by studying the developmental and tissue-specific expression using in situ hybridization and immunohistochemistry along with the creation of a mouse strain with a null allele at the P450R locus.