"Autoxidative glycosylation": free radicals and glycation theory.

Studies have shown that glycation in vitro is complicated by the ability of glucose to oxidise, in the presence of trace amounts of transition metal, generating protein-reactive ketoaldehydes, hydrogen peroxide and diverse free radicals. Protein exposed to glucose undergoes fragmentational and conformational alterations, and these, as well as thiol oxidation, appear to be caused by hydroxyl radicals. Glycofluorophore formation is dependent upon ketoaldehyde formation. It is suggested that glucose autoxidation contributes to oxidative stress in pathophysiology associated with diabetes and ageing via this newly described process of "autoxidative glycosylation".