REDUCTASE/P450 INTERACTION AFFECTS CARCINOGEN ACTIVATION

致癌物活性的调节受相互作用的影响 细胞色素P450和细胞色素P450还原酶以及其他 各种因素。我们建议定义控制相互作用的因素 还原酶和P450的活性，从而影响致癌物的激活。这个 因子包括P450和还原酶的结构域，即 膜结合域、底物结合域和结合 通过互补电荷配对相互作用的区域。我们会 通过一系列化学修饰来定义这些结构域 蛋白质和一系列定点突变研究。在每一个中 方面，这项研究的目的是具体说明在一个氨基酸残基 特定的结构域支配该结构域与底物的相互作用， 膜，或蛋白质对，以及这些残基/结构域如何协同作用 来调节致癌物的激活。 为了实现这些目标，我们将定义氨基酸 负责与临界羧基电荷配对的P450残基 还原酶的基团。我们将定义所涉及的氨基酸残基 在使用光亲和底物类似物与P450结合的底物中 定点突变。我们将定义NADPH结合区和 P450还原酶的黄素结合区。这些参数将是 对它们在底物代谢的总体控制中的作用进行评估。为 例如，我们将确定底物与P450的结合如何影响 P450与还原酶的相互作用。

Regulation of carcinogen activation is affected by interaction of cytochrome P450 and cytochrome P450 reductase, as well as by other factors. We propose to define the factors which govern the interaction of reductase and P450 and thereby influence carcinogen activation. The factors include the structural domains of P450 and reductase, i.e. membrane binding domains, substrate binding domains, and the binding domains which interact through complementary charge pairing. We will define these domains through a series of chemical modifications of the proteins and a series of site directed mutagenesis studies. In each aspect, the aim of the study is to specify which amino acid residues in a particular domain govern the interaction of that domain with substrate, membrane, or pair protein and how these residues/domains act in concert to regulate carcinogen activation. In pursuit of these goals, we will define the amino acid residues of P450s responsible for charge pairing with critical carboxyl groups of the reductase. We will define the amino acid residues involved in substrate binding to P450 using a photoaffinity substrate analogue and site directed mutagenesis. We will define the NADPH binding region and the flavin binding regions of P450 reductase. These parameters will be evaluated for their role in overall control of substrate metabolism. For example, we will determine how substrate binding to P450 affects the interaction of P450 with reductase.