Glutathione Conjugation and Protein Adduction by Environmental Pollutant 2,4-Dichlorophenol In Vitro and In Vivo
作者:Qingmei Li、Wei Li、Jiaxing Zhao、Xiucai Guo、Qian Zou、Zixin Yang、Ruixue Tian、Ying Peng、Jiang Zheng
DOI:10.1021/acs.chemrestox.0c00118
日期:2020.9.21
2,4-Dichlorophenol (2,4-DCP), an environmental pollutant, was reported to cause hepatotoxicity. The biochemical mechanisms of 2,4-DCP induced liver injury remain unknown. The present study showed that 2,4-DCP is chemically reactive and spontaneously reacts with GSH and bovine serum albumin to form GSH conjugates and BSA adducts. The observed conjugation/adduction apparently involved the addition of GSH and departure of chloride via the ipso substitution pathway. Two biliary GSH conjugates and one urinary N-acetyl cysteine conjugate were observed in rats given 2,4-DCP. The N-acetyl cysteine conjugate was chemically synthesized and characterized by mass spectrometry and NMR. As expected, 2,4-DCP was found to modify hepatic protein at cysteine residues in vivo by the same chemistry. The observed protein adduction reached its peak at 15 min and revealed dose dependency. The new findings allowed us to better understand the mechanisms of the toxic action of 2,4-DCP.
2,4-二氯苯酚(2,4-DCP)是一种环境污染物,据报道会引起肝毒性。2,4-DCP诱导肝损伤的生化机制仍不清楚。本研究发现,2,4-DCP具有化学活性,能自发与谷胱甘肽(GSH)和牛血清白蛋白(BSA)反应,形成GSH结合物和BSA加合物。观察到的结合/加合反应显然涉及通过ipso取代途径的GSH加成和氯离子的离去。在大鼠给予2,4-DCP后,观察到两种胆汁GSH结合物和一种尿N-乙酰半胱氨酸结合物。N-乙酰半胱氨酸结合物经化学合成,并通过质谱和核磁共振进行了表征。正如预期,2,4-DCP被发现通过相同的化学反应在体内修饰肝蛋白的半胱氨酸残基。观察到的蛋白加合反应在15分钟时达到峰值,并显示出剂量依赖性。这些新发现使我们更好地理解了2,4-DCP毒性作用的机制。