Rabenstein D L, Isab A A
Biochim Biophys Acta. 1982 Dec 30;721(4):374-84. doi: 10.1016/0167-4889(82)90092-1.
The binding of mercuric ion (Hg(II)) by small molecules in the intracellular region of intact human erythrocytes has been studied by 1H-NMR spectroscopy. HgCl2 added to intact erythrocytes in saline-glucose suspension is found to cross the membrane and reach an equilibrium distribution among the molecules of the erythrocyte within 4 min. In the intracellular region Hg(II) reacts with GSH and hemoglobin to form the ternary mixed-ligand complex GSH-Hg(II)-hemoglobin. The analogous complex with ergothioneine is formed after all the GSH is complexed. 1H-NMR spectra show that the GSH-Hg(II)-hemoglobin complex also forms in simpler solutions containing HgCl2, GSH and hemoglobin, whereas the complex Hg(GSH)2 predominates in solutions of GSH and HgCl2. The lifetime of the GSH in the GSH-Hg(II)-hemoglobin complex is shown to be less than 30 s, which provides direct evidence for the first time that Hg(II) complexes in biological systems are quite labile, even though their thermodynamic stability is large. The effectiveness of eight sulfhydryl-containing ligands, some of which have been used as antidotes for Hg(II) poisoning, for releasing GSH from its Hg(II) complex in hemolyzed erythrocytes was also studied. Dithiol ligands were found to be more effective than monothiols, with dithioerythritol the most effective of the dithiols.
利用核磁共振氢谱（¹H-NMR）研究了完整人类红细胞胞内区域小分子与汞离子（Hg(II)）的结合情况。发现在生理盐水-葡萄糖悬浮液中添加到完整红细胞的HgCl₂能够穿过细胞膜，并在4分钟内在红细胞分子间达到平衡分布。在胞内区域，Hg(II)与谷胱甘肽（GSH）和血红蛋白反应形成三元混合配体复合物GSH-Hg(II)-血红蛋白。在所有GSH都形成复合物后，会形成与麦角硫因的类似复合物。¹H-NMR光谱表明，在含有HgCl₂、GSH和血红蛋白的更简单溶液中也会形成GSH-Hg(II)-血红蛋白复合物，而在GSH和HgCl₂的溶液中Hg(GSH)₂占主导。结果表明GSH-Hg(II)-血红蛋白复合物中GSH的寿命小于30秒，这首次直接证明了生物系统中的Hg(II)复合物相当不稳定，尽管其热力学稳定性很高。还研究了八种含巯基配体（其中一些已被用作Hg(II)中毒的解毒剂）在溶血红细胞中从其Hg(II)复合物中释放GSH的效果。发现二硫醇配体比单硫醇更有效，其中二硫苏糖醇是最有效的二硫醇。
