Carbohydrate carbonyl mobility––the key process in the formation of α-dicarbonyl intermediates Original Research Article

Covalently cross-linked proteins are among the major modifications caused by the advanced Maillard reaction. In the present study, the formation pathway of the dideoxyosone N6-(2,3-dihydroxy-5,6-dioxohexyl)-l-lysine is shown. To elucidate the formation of this glucose-derived dideoxyosone d-lactose (O-β-d-galp-(1 → 4)-d-glcp) and d-glucose-6-phosphate were incubated with lysine in the presence of the trapping reagent o-phenylenediamine (OPD). Synthesis and unequivocal structural characterization were reported for the quinoxalines of the dideoxyosones N6-(5,6-dihydroxy-2,3-dioxohexyl)-l-lysine and N6-(2,3-dihydroxy-4,5-dioxohexyl)-l-lysine, respectively. Additionally, dicarbonyl compounds derived from d-erythrose, d-glycero-d-mannoheptose, and d-gluco-l-talooctose were synthesized and structurally characterized.