Formation pathways for lysine-arginine cross-links derived from hexoses and pentoses by Maillard processes

摘要

alpha-Dicarbonyl compounds are crucial intermediates in the cross-linking of proteins by reducing sugars in the course of the Maillard reaction. The novel dideoxyosones N~6-(2,3-dihydroxy-5,6-dioxohexyl)Iysine (9a,b) and N~6-(2-hydroxy-4,5-dioxopentyl)lysine (12) were unequivocally identified via their triazine derivatives and these alpha-diketo compounds established as precursors of the major in vivo cross-links glucosepane 11 and pentosidine 16, respectively. This new dideoxyosone class is formedin high yield in the model incubations and the underlying reaction sequence will improve our understanding of protein cross-linking and of Maillard chemistry in general.