DETOXICATION OF XENOBIOTICS IN ERYTHROCYTES

红细胞中异生物质的解毒

• 批准号: 3281016
• 负责人: YOGESH Chandra AWASTHI
• 金额: $ 12.32万
• 依托单位: UNIVERSITY OF TEXAS MED BR GALVESTON
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-07-01 至 1988-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3281016
• 关键词: affinity labeling; aminoacid analyzer; biological transport; centrifugation; chemical conjugate; chemical synthesis; detoxification; electrofocusing; environmental toxicology; erythrocyte membrane; erythrocytes; gel electrophoresis; gel filtration chromatography; glucose 6 phosphate dehydrogenase; glutathione; glutathione transferase; high performance liquid chromatography; human subject; ion exchange chromatography; thin layer chromatography; toxicant interaction; toxin metabolism

In human tissues such as liver and kidney, the mercapturic acid pathway serves as one of the important means of detoxifying the xenobiotics or foreign chemicals. However, human erythrocytes do not have complete mercapturic acid pathway. The erythrocytes contain high levels of the first enzyme of the mercapturic acid pathway, glutathione S-transferase, which conjugates glutathione (GSH) to a large number of the hydrophobic xenobiotics carrying and electrophylic center. We have recently demonstrated that the conjugate of 1-chlore-2,4-dinitrobenzene (CDNB) with GSH is formed in erythrocytes. This conjugate is not metabolized further within these cells and is actively transported out of the erythrocytes. We propose to study the mechanism of transport of the conjugates of GSH and xenobiotics from human erythrocytes. Glutathione S-transferase will be purified to homogeneity from human erythrocytes. The purified enzyme will be studied for its kinetic properties towards various xenobiotics and will also be used for the synthesis of conjugates of GSH and xenobiotics which will be used in transport studies. The kinetics of the transport of the conjugates will be studied in normal and glucose-6-phosphate dehydrogenase deficient erythrocytes, resealed ghosts and inside out vesicles formed from erythrocytes. In order to better understand the mechanism of the transport of the conjugates, the transporter protein will be purified and the transport will be studied in the reconstituted proteoliposomes. Since oxidized glutathione (GSSG) is also actively transported from the erythroctyes, we will study whether or not both GSSG and GSH-xenobiotic conjugates are transported via the same transporter protein. The proposed studies will be of great significance in understanding the mechanisms by which erythrocytes detoxify xenobiotics and environmental pollutants.

在肝脏和肾脏等人体组织中，硫醇酸途径 是外源物质解毒的重要手段之一 外国化学品。 然而，人类红细胞并不具有完整的 硫醇尿酸途径。 红细胞含有高水平的 硫醇酸途径的第一种酶，谷胱甘肽S-转移酶， 它将谷胱甘肽 (GSH) 与大量疏水性分子结合 外源物质携带和亲电中心。 我们最近有 证明 1-氯-2,4-二硝基苯 (CDNB) 与 GSH 在红细胞中形成。 该结合物不会进一步代谢 在这些细胞内并被主动转运出红细胞。 我们 拟研究 GSH 缀合物的转运机制 来自人类红细胞的异生素。 谷胱甘肽 S-转移酶将 从人红细胞中纯化至同质。 纯化后的酶将 研究其对各种异生物质的动力学特性，并将 也可用于合成 GSH 和异生素的缀合物， 将用于交通研究。 运输动力学 将在正常酶和葡萄糖-6-磷酸脱氢酶中研究缀合物 红细胞缺陷、重新密封的鬼影和由内而外形成的囊泡 红细胞。 为了更好地理解运输机制 结合物中，转运蛋白将被纯化，并且 将在重构的蛋白脂质体中研究运输。 自从 氧化型谷胱甘肽 (GSSG) 也积极从 erythroctyes，我们将研究 GSSG 和 GSH-xenobiotic 是否同时存在 缀合物通过相同的转运蛋白进行转运。 拟议的 研究对于理解其机制具有重要意义 红细胞可以解毒外源物质和环境污染物。