Controversial behavior of aminoguanidine in the presence of either reducing sugars or soluble glycated bovine serum albumin

Abstract

The elucidation of the controversial inhibitory effect of aminoguanidine (AG) on the cross-linking and fluorescent advanced glycation end products (AGEs) formation during long-term in vitro glycation of type I collagen with 250 mM reducing sugars or 0.5 mg/ml soluble glycated bovine serum albumin (AGE-BSA) was researched. Chromatographic and SDS–PAGE analyses revealed the formation of aggregates during collagen glycation. AG at all concentrations (5–80 mM) prevented the cross-linking of collagen peptides with monosaccharides but an increase in fluorescence with a maximum value at 10 mM AG was noticed. In the presence of AGE-BSA, AG prevented the cross-linking process and decreased the fluorescence levels in a concentration-dependent manner. Our results suggest that AG is an efficient inhibitor of collagen cross-linking and the highest increase in fluorescence due to reducing sugars and AG can be explained by the competition between guanidine group of AG and arginine residues of some protein-bound dideoxyosones, which could form fluorescent compounds.