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Main Title Reduction and Binding of Arsenate and Dimethylarsinate by Glutathione: A Magnetic Resonance Study.
Author Delnomdedieu, M. ; Basti, M. M. ; Otvos, J. D. ; Thomas, D. J. ;
CORP Author North Carolina Univ. at Chapel Hill. Center for Environmental Medicine and Lung Biology. ;North Carolina State Univ. at Raleigh. Dept. of Biochemistry.;Health Effects Research Lab., Research Triangle Park, NC. Pharmacokinetics Branch.
Publisher c1994
Year Published 1994
Report Number EPA-R-817643; EPA/600/J-94/533;
Stock Number PB95-148953
Additional Subjects Biochemistry ; Nuclear magnetic resonance ; Arsenic compounds ; Reduction(Chemistry) ; Pollutants ; Glutathione ; Complex compounds ; Oxidation ; Toxicity ; Arsenates ; Chemical equilibrium ; Metabolism ; Reprints ; Arsinate/dimethyl ; Arsenites ; Chemical reaction mechanisms
Library Call Number Additional Info Location Last
NTIS  PB95-148953 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 19p
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. (Copyright (c) 1994 Elsevier Science Ireland Ltd.)