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.

在人体组织如肝脏和肾脏中，巯基尿酸途径 作为解毒外源性物质的重要手段之一， 外国化学品 然而，人红细胞没有完整的 巯基尿酸途径 红细胞含有高水平的 巯基尿酸途径的第一种酶，谷胱甘肽S-转移酶， 其将谷胱甘肽（GSH）结合到大量的疏水的 外源物质携带和亲电中心。 我们最近 证明了1-氯-2，4-二硝基苯（CDNB）与 GSH在红细胞中形成。 该结合物未进一步代谢 在这些细胞内，并被主动转运出红细胞。 我们 建议研究谷胱甘肽和谷胱甘肽结合物的转运机制， 从人红细胞中提取外源性物质。 谷胱甘肽S-转移酶将是 从人红细胞中纯化至均一。 纯化的酶将 研究其对各种异生物质的动力学特性， 也可用于合成GSH和异生物质的缀合物， 将用于交通研究。 的运输动力学 将在正常和葡萄糖-6-磷酸脱氢酶中研究结合物 缺乏红细胞，重新密封的幽灵和由内而外的囊泡形成， 红细胞 为了更好地理解运输的机制， 在缀合物中，转运蛋白将被纯化， 将在重构的脂蛋白体中研究转运。 以来 氧化型谷胱甘肽（GSSG）也积极从 红细胞，我们将研究是否GSSG和GSH-异生物质 缀合物通过相同的转运蛋白转运。 拟议 这些研究对于理解这些机制具有重要意义， 红细胞可以解毒异生物质和环境污染物。