ARYL AND ALCOHOL SULFOTRANSFERASES IN DRUG METABOLISM

这项研究的长期目标是更好地理解 芳基磺基转移酶(AST)IV和醇基磺基转移酶StA的作用 细胞毒性、免疫学、致突变和致癌反应 拥有或被生物转化的药物和其他外来生物物质 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、硝基芳香族和芳胺的外来生物 具有苄基碳的异类化合物的功能 易受代谢氧化影响的原子。这项研究建议 在这种应用的前提下，定量分析 磺基转移酶的催化特性和作用机制及其相互作用 区域内的本地化和分布对于准确 预测分子内大分子共价变化的可能性 暴露于具有这些物质的外源物质后的单个细胞 有机官能团。对两国关系的考察 AST IV和STA将侧重于划定 它们对苯酚、苯甲醇、N-羟基芳胺、 和芳基异羟肟酸作为底物和/或抑制剂。量化 将使用免疫组织化学方法来确定重叠和/或 足内定位和分布中的互补性 雄鱼和雄鱼的肝脏、皮肤、肺和鼻黏膜中的两种酶 雌性老鼠。 除了这些关于生物多样性和地方性的研究 这两种磺基转移酶的催化机理研究 AST IV将继续进行。这些研究将包括Active 定点亲和标记和多肽测序 阐明多肽在两个主要区域的结构 活性部位(即，PAPs结合部位和 硫酰受体)。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 对天冬氨酸转氨酶IV的催化机理有更全面的了解。 因此，在这个项目中使用的多方面方法将导致 显著提高了对以下两个主要领域的理解 磺基转移酶参与了硫酸酯的形成 与化学致癌和其他 暴露于多种外源物质后的毒性反应。

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.