ARYL AND ALCOHOL SULFOTRANSFERASES IN DRUG METABOLISM

药物代谢中的芳基和醇磺基转移酶

• 批准号: 6632936
• 负责人: MICHAEL W DUFFEL
• 金额: $ 23.15万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-08-01 至 2005-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6632936
• 关键词: Kupffer's cell; active sites; affinity labeling; alcohols; catalyst; chemical models; densitometry; drug metabolism; enzyme activity; enzyme inhibitors; enzyme mechanism; enzyme structure; enzyme substrate; hydroxysteroids; immunocytochemistry; in situ hybridization; laboratory rat; liver cells; model design /development; site directed mutagenesis; stereochemistry; sulfotransferase; tamoxifen

DESCRIPTION (Adapted from the applicant's abstract): The sulfation of benzylic alcohols, allylic alcohols, and N-hydroxy arylamines is often the critical step in their biotransformation into chemically reactive metabolites that can form covalent bonds with cellular macromolecules, the initial step leading to various toxicological responses including cellular necrosis, mutagenesis, and carcinogenesis. The long-term goal of this research is to more fully understand and predict the roles that aryl and alcohol sulfotransferases play in these toxic responses. The research proposed in this application addresses fundamental aspects of the molecular recognition of substrates and inhibitors as well as intrahepatic expression of aryl sulfotranferase IV (AST IV) and alcohol (hydroxysteroid) sulfotransferase (STa). Specific Aims 1 and 2 of the proposal involve the development and refinement of three-dimensional models of structure-activity relationships for AST IV and STa. Aim 1 is based on the hypothesis that specific amino acid residues lining the sulfuryl acceptor sites of these enzymes are major determinants of the molecular recognition and stereoselectivity of these enzymes for substrates and inhibitors. This hypothesis will be tested using a multi-faceted approach wherein kinetic analyses of stereochemically defined substrates are coupled with site-directed mutagenesis, protein homology modeling, and conformer modeling analysis based on structure-alignment. Investigations on stereochemical aspects of the sulfation of alpha-hydroxytamoxifen (a potentially critical step involved in the carcinogenic effects seen in a small percentage of women treated with this drug) and several related model allylic alcohols will also be continued. Aim 2 is centered on refinement of the homology models from the C-terminal regions of AST IV and STa. In the third specific aim, homology models and three-dimensional structure-activity relationships will be utilized to design, synthesize, and evaluate isoform-specific inhibitors of rat AST IV and STa. Results from these studies on isoform-specific inhibitors will then be extended to the related human isoforms of aryl and alcohol sulfotransferases. Finally, Specific Aim 4 of the proposal is to explore the expression and activity of AST IV and STa within both cholangiocytes (bile duct epithelial cells) and Kupffer cells, two types of nonparenchymal cells that play critical roles in the pathophysiology of the liver. The results to be forthcoming from the proposed continuation of this grant will, therefore, provide significant new insight into factors, such as molecular recognition of substrates and inhibitors and intrahepatic localizations, that regulate aryl and alcohol sulfotransferase-mediated xenobiotic and endobiotic metabolism and their roles in liver pathophysiology.

描述（改编自申请人的摘要）：苄基的硫酸化 醇、烯丙醇和 N-羟基芳胺通常是关键步骤 在它们生物转化为化学反应性代谢物的过程中，可以形成 与细胞大分子形成共价键，这是导致 各种毒理学反应，包括细胞坏死、诱变和 致癌作用。这项研究的长期目标是更全面地了解 并预测芳基和醇磺基转移酶在这些中发挥的作用 毒性反应。本申请中提出的研究涉及 底物和抑制剂分子识别的基本方面 以及芳基磺基转移酶 IV (AST IV) 的肝内表达和 醇（羟基类固醇）磺基转移酶（STa）。具体目标 1 和 2 提案涉及三维模型的开发和完善 AST IV 和 STa 的构效关系。目标 1 基于 假设硫酰受体位点内衬有特定氨基酸残基 这些酶是分子识别和识别的主要决定因素 这些酶对底物和抑制剂的立体选择性。这 假设将使用多方面的方法进行检验，其中动力学 立体化学定义的底物的分析与定点结合 基于诱变、蛋白质同源性建模和构象异构体建模分析 关于结构调整。立体化学方面的研究 α-羟基他莫昔芬的硫酸化（涉及的潜在关键步骤 在接受这种治疗的一小部分女性中发现了致癌作用 药物）和几种相关模型烯丙醇也将继续。目标2 集中于从 C 末端区域细化同源模型 AST IV 和 STa。在第三个具体目标中，同源模型和 三维结构-活动关系将用于设计， 合成并评估大鼠 AST IV 和 STa 的异构体特异性抑制剂。 这些关于异构体特异性抑制剂的研究结果将得到扩展 芳基和醇磺基转移酶的相关人类亚型。最后， 该提案的具体目标4是探索AST的表达和活性 胆管细胞（胆管上皮细胞）和 Kupffer 内的 IV 和 STa 细胞，两种类型的非实质细胞，在 肝脏的病理生理学。拟议的结果即将公布 因此，继续提供这笔赠款将提供重要的新见解 因素，例如底物和抑制剂的分子识别以及 肝内定位，调节芳基和酒精 磺基转移酶介导的外源性和内源性代谢及其作用 在肝脏病理生理学中。