STUCTURE FUNCTION AND REGULATION OF NADPH CYTOCHROME P450 OXIDOREDUCTASE

在生物化学意义上，混合功能氧化酶系统代表了 人类与环境之间的第一道防线该系统 负责早期代谢步骤，在他们的解毒 外源性物质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对外来化合物的反应是不一致的。 细胞的最终命运取决于这些关键酶的活性水平。 内切酶 这一建议是我们正在进行的研究的延伸， 结构NADPH-细胞色素P450的功能和调节 氧化还原酶（P450 R）和细胞色素3A家族。四大领域将 在下一个授予期间解决。第一个将检查那些 还原酶分子的结构特征， 保持黄素结构域的最佳排列和完整性。三 将对具体地区进行分析。这些是相互连接的黄素 结构域，羧基末端区域，这是重要的结构 FAD/NADPH结合结构域的功能特征，是 电子从NADPH进入，铰链区靠近FMN 域第二个领域将侧重于确定 P450 R的表面负责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，P450 R和CYP 3A 23基因的调节将被 调查，以更好地了解控制因素 这些酶的细胞水平。四、P450 R的生物学作用 将通过研究发育和组织特异性 表达使用原位杂交和免疫组织化学沿着与 在P450 R基因座处具有无效等位基因的小鼠品系的产生。

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.