EPR investigation of the oxovanadium(IV) complexes formed by the tripeptide glutathione and some related ligands in aqueous solution.

Complex formation between oxovanadium(IV) and glutathione (gamma-L-glutamyl-L-cysteinylglycine, GSH) was investigated in aqueous solution by EPR and electron absorption spectroscopy to identify the complexed species that were reported to form upon reduction of exogenous vanadium(V) in cellular systems. The complexing behavior of the related ligands glycine, N-acetyl-glycine, 3-mercaptopropionic acid, cysteamine, L-cysteine, N-acetyl-L-cysteine, N-acetyl-cysteamine, and oxidized glutathione (GSSG) was also examined in order to have suitable reference models. The results are compared with those reported previously.