DIHYDRODIOL DEHYDROGENASE & PAH DETOXIFICATION

二氢二醇脱氢酶

• 批准号: 3071848
• 负责人: Trevor M Penning
• 金额: $ 6.88万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-02-01 至 1993-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3071848
• 关键词: DNA; alcohol dehydrogenase; benzopyrenes; carbopolycyclic compound; chemical addition; chemical carcinogen; chemical conjugate; cis trans isomerization; cysteine; detoxification; diol; enzyme mechanism; enzyme substrate; epoxides; glutathione; glutathione transferase; human tissue; indomethacin; isozymes; laboratory rat; liver metabolism; naphthalenes; neoplastic cell; oxidoreductase inhibitor; phenanthrene; postmortem; quinones

This application requests support for a Research Career Development Award for continuation of a systematic study of the role of dihydrodiol dehydrogenase in the detoxification of proximate and ultimate carcinogens of polycyclic aromatic hydrocarbons (PAH). The research programs includes chemical, biochemical, cellular and human studies designed to provide information on the role of this enzyme in PAH metabolism. We have shown that the homogeneous dihydrodiol dehydrogenase from rat liver cytosol oxidizes a variety of non-K-region-trans dihydrodiols of carcinogenic PAH to the corresponding ortho- quinones which can be trapped as mercaptoethanol adducts. To obtain information on this alternative pathway of proximate carcinogen metabolism, the reactivity of non-K-region ortho- quinone products towards cellular nucleophiles will be examined, the influence of bay-region methylation on reactivity will be determined, the ability of glutathione to enhance enzymatic rates of trans-dihydrodiol oxidation by trapping the ortho-quinone products will be assessed, structures of putative quinone- glutathione adducts will be elucidated, and the ability of these ortho-quinone products to act as substrates for highly purified preparations of rat liver glutathione transferases will be determined. The involvement of the homogeneous dihydrodiol dehydrogenase in ultimate carcinogen metabolism will be explored by using the stable anti-diol-epoxides of naphthalene and phenanthrene and the anti-diol epoxide of benzo(a)pyrene (BP) as substrates. Cellular studies will exploit the findings that the rat hepatoma cell line (H-4II-e) contains dihydrodiol dehydrogenase that is exquisitely sensitive to inhibition by indomethacin and 6- medroxyprogesterone acetate. By studying the metabolism of the (3H)-7,8-trans-dihydrodiol of BP in these cells, in the presence and absence of these drugs, the contribution of dihydrodiol dehydrogenase to the detoxification of PAH in whole cells will be assessed. If this enzyme plays a significant role these drugs should evaluate levels of anti-diol epoxides and BP-DNA adducts. To determine if dihydrodiol dehydrogenase plays a role in PAH metabolism in humans, liver autopsy samples will b analyzed for this enzyme activity, activities will be separated by chromatography and isozymes which oxidize the trans-7,8- dihydrodiol of BP will be characterized.

此申请请求对研究职业的支持 继续系统研究发展奖 二氢二醇脱氢酶在解毒中的作用 多环芳烃的直接致癌物和最终致癌物 碳氢化合物（PAH）。 研究项目包括化学、 生化、细胞和人体研究旨在提供 有关该酶在 PAH 代谢中的作用的信息。 我们已经证明，同质二氢二醇脱氢酶 来自大鼠肝细胞质氧化多种非 K 区反式 致癌性 PAH 的二氢二醇对应的邻位 醌类化合物可以作为巯基乙醇加合物被捕获。 到 获取有关该替代途径的信息 致癌物代谢，非K区邻位的反应性 将检查针对细胞亲核试剂的醌产品， 湾区甲基化对反应性的影响将是 确定，谷胱甘肽提高酶促速率的能力 通过捕获邻醌来氧化反式二氢二醇 产品将被评估，假定醌的结构 谷胱甘肽加合物将被阐明，并且这些的能力 邻醌产品用作高纯度的底物 大鼠肝谷胱甘肽转移酶制剂 决定。 均质二氢二醇脱氢酶的参与 将利用以下方法探索致癌物的最终代谢 萘和菲的稳定抗二醇环氧化物以及 以苯并（a）芘（BP）的抗二醇环氧化物为底物。 细胞研究将利用大鼠肝癌的发现 细胞系（H-4II-e）含有二氢二醇脱氢酶， 对吲哚美辛和 6- 的抑制极其敏感 醋酸甲羟孕酮。 通过研究新陈代谢 这些细胞中存在 BP 的 (3H)-7,8-反式二氢二醇 如果没有这些药物，二氢二醇的贡献 脱氢酶对全细胞中 PAH 的解毒作用 评估。 如果这种酶发挥重要作用，这些药物 应评估抗二醇环氧化物和 BP-DNA 加合物的水平。 确定二氢二醇脱氢酶是否在 PAH 中发挥作用 人类的新陈代谢，将分析肝脏尸检样本 这种酶的活性，活性将被分开 氧化反式 7,8- 的色谱法和同工酶 将表征BP的二氢二醇。