3-Deoxyglucosone crosslinks proteins under physiological conditions.

Abstract

Nonenzymatic glycosylation, which occurs in the initial stage of the Maillard reaction between proteins and glucose, has been reported for various proteins, and in the later stage of the reaction, glycosylated proteins are known to undergo complex chemical changes such as impairment of some amino acid residues, discoloration, development of fluorescence and crosslinking.1>2) Amongthese chemical changes, the crosslinking or glucose-mediated polymerization of proteins has been hypothesized to be responsible for the aging of tissues or accelerated aging in diabetes.3) Actually, the crosslinking of long-lived proteins such as collagen and lens crystallin has been observed and shown to increase with aging and diabetes.4'5) Therefore, much attention is being focused on elucidation of the crosslinking mechanism. Recently, Pongor et al.6) isolated one of the major fluorescent chromophores, 2-(2-furoyl)-4(5)-(2-furanyl)-l//-imidazole (FFI), from the acid hydrolysates of browned poly(L-lysine) and browned BSA. They suggested that e-fructose-