REDUCTION AND BINDING OF ARSENATE AND DIMETHYLARSINATE BY GLUTATHIONE - A MAGNETIC-RESONANCE STUDY
REDUCTION AND BINDING OF ARSENATE AND DIMETHYLARSINATE BY GLUTATHIONE - A MAGNETIC-RESONANCE STUDY
复制标题
DOI：
10.1016/0009-2797(94)90099-x
复制
发表时间：
1994-02-01
影响因子：
5.1
通讯作者：
THOMAS, DJ
中科院分区：
文献类型：
--
作者：
DELNOMDEDIEU, M;BASTI, MM;THOMAS, DJ
通过观察还原型谷胱甘肽的质子和~(13)C原子核的化学位移，表征了亚砷酸盐、亚砷酸盐和二甲基砷与该三肽的相互作用。这些光谱研究表明，砷的还原和络合是一个两步过程。最初，氧化2摩尔的谷胱甘肽将砷还原为亚砷酸盐。然后，3摩尔的谷胱甘肽被消耗以形成谷胱甘肽-亚砷酸盐络合物。与亚砷酸盐类似的实验证实了(谷胱甘肽)3-亚砷酸盐的络合物；然而，没有检测到氧化的谷胱甘肽。亚砷酸根与谷胱甘肽的结合部位为半胱氨酸基。谷胱甘肽-亚砷酸盐络合物在pH值1.5-7.0-7.5范围内稳定。在较高的pH下，发生解离释放还原型谷胱甘肽。当谷胱甘肽与二甲基砷酸盐的比例为3时，氧化的谷胱甘肽还与还原成三价的二甲基砷酸偶联，然后形成1：1的谷胱甘肽-二甲基砷酸盐络合物。还原型谷胱甘肽在砷代谢中的作用与先前描述的该制剂对砷的组织毒性的影响是一致的。
By observing the chemical shifts of the proton and carbon-13 nuclei of reduced glutathione, the interactions of arsenate, arsenite and dimethylarsinate with this tripeptide have been characterized. These spectral studies show the reduction and complexation of arsenic to be a two-step process. Initially, the oxidation of 2 mol of glutathione reduces arsenate to arsenite. Then, 3 mol of glutathione are consumed in the formation of a glutathione-arsenite complex. Similar experiments with arsenite identified a (glutathione)3-arsenite complex; however, no oxidized glutathione was detected. The arsenite binding site in the glutathione-arsenite complex is the cysteinyl sulfhydryl. The glutathione-arsenite complex is stable over the pH range from 1.5 to 7.0-7.5. At higher pH, dissociation occurs releasing reduced glutathione. For a glutathione to dimethylarsinate ratio of 3, oxidized glutathione is also coupled with a reduction to trivalent dimethylarsinous acid, prior to the formation of a 1:1 glutathione-dimethylarsinite complex. The role of reduced glutathione in the metabolism of arsenic is consistent with the previously described effects of this agent on the organismic toxicity of arsenic.