Activation of androgen biosynthesis and drug metabolism by cytochrome b5

细胞色素 b5 激活雄激素生物合成和药物代谢

• 批准号: 7939798
• 负责人: RICHARD J. AUCHUS
• 金额: $ 9.4万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-30 至 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7939798
• 关键词: Adverse effects; Algorithms; Anabolism; Androgens; Biochemistry; CYP17A1 gene; Carbon; Cardiovascular Diseases; Cessation of life; Chemicals; Chemistry; Complex; Conflict (Psychology); Cytochrome P450; Cytochromes; Cytochromes b5; Data; Disease; Dissociation; Electron Transport; Endometrial Carcinoma; Enzymes; Fertility; Hirsutism; Histology; Hormones; Human; In Vitro; Individual; Infertility; Kinetics; Knowledge; Laboratories; Malignant Neoplasms; Malignant neoplasm of prostate; Mediating; Microscopic; Mixed Function Oxygenases; Modeling; Morbidity - disease rate; Mus; Pharmaceutical Preparations; Physiology; Polycystic Ovary Syndrome; Preparation; Production; Prostatic hypertrophy; Reaction; Risk; Sex Differentiation; Stanolone; Steroid 17-alpha-monooxygenase; Steroid 21-Monooxygenase; Steroids; Testis; Testosterone; Woman; drug metabolism; human disease; in vivo; leydig interstitial cell; male; mortality; novel strategies; older women

All 19-carbon androgens derive from 21-carbon steroids via sequential 17¿-hydroxylase and 17,20-lyase activities of cytochrome P450c17 (CYP17A1). The complex chemistry of the 17,20-lyase reaction is selectively stimulated up to 10-fold by cytochrome b5 (b5) in vitro. In contrast to the interactions of b5 with some other cytochromes P450, which apparently involve electron transfer from b5, our data argue that b5 allosterically activates the 17,20-lyase activity of CYP17A1. We have identified a specific region of b5 that is critical for stimulation of 17,20-lyase activity and have shown that the magnitude of this stimulation is substrate-dependent. We now propose to elucidate the importance of this action of b5 on 17,20-lyase activity and androgen synthesis in vivo and to compare the mechanistic and structural features of the b5-CYP17A1 interaction with b5 action on other P450-mediated reactions, in preparation for a detailed interrogation of the mechanism of b5 action on CYP17A1. To first prove that b5 is essential for androgen biosynthesis, we will generate and characterize mice lacking b5 in the testis for Aim 1. We will characterize the fertility, hormone production, and testicular histology of these mice. The enzymatic activity of the testes will be studied in detail. In Aim 2, we will determine if residues on b5 that are required for stimulating 17,20-lyase activity are also essential for modulating the activities of other cytochromes P450 and begin to determine whether the same microscopic steps are involved for all P450 enzymes. We thus will define the importance of b5 action on CYP17A1 in mammalian physiology, and we will begin to ascertain if the mechanism of action is similar to b5 action on other cytochromes P450. This knowledge will provide a novel approach for suppressing androgen production, by targeting the CYP17A1-b5 interaction.

所有 19 碳雄激素均通过连续 17¿ 衍生自 21 碳类固醇-羟化酶 和细胞色素 P450c17 (CYP17A1) 的 17,20-裂解酶活性。 17,20-裂解酶反应被细胞色素 b5 (b5) 选择性刺激高达 10 倍 与 b5 与其他一些细胞色素 P450 的相互作用相反， 显然涉及 b5 的电子转移，我们的数据表明 b5 变构 激活 CYP17A1 的 17,20-裂解酶活性 我们已经确定了 b5 的特定区域。 这对于刺激 17,20-裂解酶活性至关重要，并且已表明 我们现在建议阐明这种刺激的重要性。 b5 对体内 17,20-裂合酶活性和雄激素合成的作用 比较 b5-CYP17A1 与 b5 相互作用的机制和结构特征 对其他 P450 介导的反应的作用，为详细询问做准备 b5 对 CYP17A1 的作用机制。 为了首先证明 b5 对于雄激素生物合成至关重要，我们将生成并 为目标 1 描述睾丸中缺乏 b5 的小鼠的特征。我们将描述生育能力的特征， 这些小鼠的激素产生和睾丸组织学。 在目标 2 中，我们将详细研究测试，以确定 b5 上的残基是否是。 刺激 17,20-裂解酶活性所需的物质对于调节 其他细胞色素P450的活性并开始确定是否相同 所有 P450 酶都涉及微观步骤，因此我们将定义 b5 对 CYP17A1 的作用在哺乳动物生理学中的重要性，我们将开始 确定其作用机制是否与 b5 对其他细胞色素 P450 的作用相似。 这些知识将提供一种抑制雄激素产生的新方法，通过 靶向 CYP17A1-b5 相互作用。