DETOXIFICATION OF METALS--IN VITRO AND IN VIVO STUDIES

金属解毒——体外和体内研究

• 批准号: 6106235
• 负责人: H VASKEN APOSHIAN
• 金额: $ 12.65万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-04-01 至 2000-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6106235
• 关键词: SDS polyacrylamide gel electrophoresis; affinity chromatography; animal tissue; arsenic; autoradiography; biotransformation; detoxification; environmental contamination; environmental toxicology; erythrocytes; gas chromatography; glutathione; human tissue; laboratory mouse; laboratory rabbit; metal metabolism; metalloproteins; methylation; methyltransferase; protein purification; reduction; toxicant interaction; waste disposal; waste treatment

Description: Arsenic and other toxic metals and metalloids are known to have been dumped at numerous superfund sites. Two important biological mechanisms for detoxifying metal ions are protein binding, and methylating them via enzymes such as methyl transferases which use S- adenosylmethionine and/or vitamin B12 as coenzymes. This appears to be true for arsenic, selenium and possibly lead. The molecular mechanisms by which methylations are accomplished are unknown. The enzyme reactions for the biotransformation of arsenate/arsenite are unknown. Enzyme reactions for the biotransformation of arsenate/arsenite to the less toxic methylarsonate and much less toxic dimethylarsinate have been studied only to a limited extent using crude, impure enzyme homogenates of bacteria, fungi or the rat. There have also been limited, in vivo, metabolic studies in experimental animals and humans in which arsenic compounds were given and the metabolites in the urine identified. This project deals with the isolation and purification of human enzymes and binding proteins that detoxify arsenate/arsenite in order to study the molecular mechanisms of these detoxifications. In this way, for the first time, the enzymatic mechanisms for the detoxification of arsenate/arsenite in humans will be understood. Once the arsenic biotransforming enzymes have been characterized, other metal ions such as lead, selenium, cadmium, as well as, halogenated aromatic hydrocarbons will be studied to see if they inhibit the enzymatic biotransformation of arsenic. The control and regulation of these purified enzymes will be studied and inhibitors and stimulators of the enzymes will be studied. Urine of animals challenged with arsenate will be tested for methyltransferase activities to determine whether these enzymes can be used as biological indicators of the body's concentration of toxicologically active forms of arsenic. A challenge test for arsenic in humans using DMPS (2,3- dimercaptopropane-1-sulfonic acid) will be developed. Such a challenge test will be helpful for determining the exposure of humans to arsenic and will be useful to determine arsenic exposure of humans near superfund sites.

描述：已知砷和其他有毒金属和金属 已被抛弃在许多超级基金网站上。两个重要的生物学 排毒金属离子的机制是蛋白质结合，并且 通过酶，例如使用S-的甲基转移酶甲基甲基 腺苷硫氨酸和/或维生素B12作为辅酶。这似乎是 对于砷，硒和可能的铅而言是正确的。分子机制 通过完成甲基化的方法是未知的。酶反应 对于砷/砷的生物转化是未知的。酶 砷/砷对生物转化的反应 有毒的甲基甲酸甲酯和毒性二甲基苯甲酸酯已经是 仅使用粗酶匀浆在有限程度上进行研究 细菌，真菌或大鼠。在体内也有限 砷的实验动物和人类的代谢研究 给出了化合物，并在尿液中的代谢产物中给出了代谢产物。这 项目涉及人类酶的隔离和纯化 结合蛋白质，将砷/砷排毒以研究 这些解毒的分子机制。这样， 第一次，用于排毒的酶机制 人类中的砷/砷酸盐将被理解。一旦砷 已经表征了生物转化酶，其他金属离子 作为铅，硒，镉以及卤代芳基芳族 将研究碳氢化合物，以查看它们是否抑制酶促 砷的生物转化。这些的控制和调节 将研究纯化的酶并抑制剂和刺激剂 将研究酶。用砷挑战的动物的尿液会 测试是否有甲基转移酶活性，以确定这些是否是否 酶可以用作人体浓度的生物学指标 毒素活性形式的砷。一个挑战测试 使用DMP（2,3-二甲状腺丙烷-1-磺酸）的人类砷 将开发。这样的挑战测试将有助于 确定人类暴露于砷，对 确定超级基金地点附近人类的砷暴露。