Reduction and binding of arsenate and dimethylarsinate by glutathione: a magnetic resonance study

Chem Biol Interact. 1994 Feb;90(2):139-55. doi: 10.1016/0009-2797(94)90099-x.


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.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Arsenates / chemistry
  • Arsenates / metabolism*
  • Arsenites / chemistry
  • Arsenites / metabolism
  • Binding Sites
  • Cacodylic Acid / chemistry
  • Cacodylic Acid / metabolism*
  • Drug Stability
  • Glutathione / chemistry
  • Glutathione / metabolism*
  • Hydrogen-Ion Concentration
  • In Vitro Techniques
  • Magnetic Resonance Spectroscopy
  • Molecular Structure
  • Oxidation-Reduction


  • Arsenates
  • Arsenites
  • Cacodylic Acid
  • Glutathione
  • arsenite
  • arsenic acid