Abstract
The elevation of such dicarbonyl compounds as glyoxal and the depletion of GSH occur simultaneously in diabetic patients. Enabling a nonenzymatic glycation reaction with GSH and glyoxal is therefore proposed. However, the reaction mechanism for GSH and glyoxal has not been precisely defined. We isolated in this study the major products obtained by the reaction of GSH and glyoxal under physiological conditions, and clarified the chemical structure of these compounds by MS and NMR analyses for the first time. We identified the major product after 24 h as N-[3-(2,5-dioxomorpholin-3-yl)propanoyl]cysteinylglycine, and the one after 30 min as N-glycoloyl-γ-glutamylcysteinylglycine (the intermediate of the former compound). Our results suggest that GSH reacted with glyoxal at the α-NH2 group of the glutamate residue, but not at the SH group of the cysteine residue.
