ARYL AND ALCOHOL SULFOTRANSFERASES IN DRUG METABOLISM

这项研究的长期目标是更好地了解 芳基磺基转移酶 (AST) IV 和醇磺基转移酶 STa 发挥作用 细胞毒性、免疫学、诱变和致癌反应 具有或经过生物转化的药物和其他外源物质 转化为含有芳基异羟肟酸、N-羟基芳胺或 苯甲醇官能团。 这些官能团通常是 作为多种不同药物的中间代谢物 和其他含有芳胺、硝基芳族化合物和芳酰胺的外源物质 功能以及具有苄基碳的外源物质 易受代谢氧化影响的原子。 研究提出 在本申请中基于定量分析的前提 磺基转移酶的催化特异性和机制及其 组织内定位和分布对于准确地定位和分布至关重要 预测内大分子共价改变的潜力 暴露于具有这些特性的异生物质后的单个细胞 有机官能团。 之间关系的调查 AST IV 和 STa 将重点描述重叠程度 它们对酚类、苯甲醇、N-羟基芳胺、 和芳基异羟肟酸作为底物和/或抑制剂。 定量 免疫组织化学方法将用于确定重叠和/或 组织内定位和分布的互补性 男性和女性的肝脏、皮肤、肺和鼻粘膜中存在两种酶 雌性老鼠。 除了这些关于特殊性和本地化的研究之外 这两种磺基转移酶的催化机制研究 AST IV 将继续进行。 这些研究将纳入积极的 定点亲和标记和肽测序 阐明肽的两个主要区域的结构 活性位点（即 PAPS 结合位点和 硫酰基受体）。 亲和标记实验的结果将 然后指导定点突变的合作研究以提供 对 AST IV 的催化机制有更全面的了解。 因此，该项目中采用的多方面方法将导致 显着提高了对两个专业的理解 磺基转移酶参与硫酸酯的形成， 与化学致癌和其他物质的发生有关 接触大量异生物质后的毒性反应。

The long-term goal of this research is to better understand the role that aryl sulfotransferase (AST) IV and alcohol sulfotransferase STa play in the cytotoxic, immunologic, mutagenic, and carcinogenic responses to drugs and other xenobiotics that either possess or are biotransformed into metabolites containing arylhydroxamic acid, N-hydroxy arylamine, or benzylic alcohol functional groups. These functional groups are usually encountered as intermediary metabolites of a multitude of different drugs and other xenobiotics containing arylamine, nitroaromatic, and arylamide functionalities as well as of xenobiotics possessing benzylic carbon atoms that are susceptible to metabolic oxidation. The research proposed in this application is based on the premise that quantitative analyses of the catalytic specificities and mechanisms of sulfotransferases and their intratissue localizations and distributions are essential for accurately predicting the potential for covalent alteration of macromolecules within individual cells following exposure to xenobiotics that possess these organic functional groups. Investigations on the relationships between AST IV and STa will focus on delineation of the degree of overlap in their specificities for phenols, benzylic alcohols, N-hydroxy arylamines, and arylhydroxamic acids as substrates and/ or inhibitors. Quantitative immunohistochemical methods will be used to determine overlap and/or complementarity in the intratissue localizations and distributions of the two enzymes in liver, skin, lung, and nasal mucosa of both male and female rats. In addition to these studies on the specificities and localizations of these two sulfotransferases, investigations on the catalytic mechanism of AST IV will be continued. These studies will incorporate active site-directed affinity labeling and peptide-sequencing in order to elucidate the structures of peptides at the two major regions of the active site (i.e., the PAPS-binding site and the binding site for a sulfuryl acceptor). Results from the affinity labeling experiments will then guide collaborative studies on site-directed mutagenesis to provide a more complete understanding of the catalytic mechanism of AST IV. Thus, the multifaceted approach utilized in this project will result in a significantly improved understanding of two of the major sulfotransferases involved in the formation of sulfuric acid esters that are implicated in the occurrence of chemical carcinogenesis and other toxic responses following exposure to numerous xenobiotics.