Inhibitory effect of a Chinese quince seed peptide on protein glycation: A mechanism study

Non-enzymatic glycation can cause the formation and accumulation of advanced glycation end products (AGEs), and it poses great threats to human health. It is urgent to search for safe and efficient inhibitors to prevent reducing sugar induced protein glycation. In this study, we investigated the anti-glycation activity and mechanism of an identified peptide, Asparagine-Tyrosine-Arginine-Arginine-Glutamic acid (NYRRE) from Chinese quince seed protein hydrolysate, by multispectroscopy, confocal imaging, and computational molecular simulation. Firstly, it was found that NYRRE could scavenge hydroxyl radicals and chelate Fe2+. Besides, the NYRRE was effective in every stage of fructose induced bovine serum albumin (BSA) glycation. The NYRRE could reduce the formation of fructosamine, carbonyl compounds, glycoxidation products and β-amyloid structure. Meanwhile, NYRRE could protect thiol groups and stabilize the spatial conformation of BSA. The NYRRE presented strong inhibition in fluorescent AGEs, and 68.19% of total AGEs formation was prevented with NYRRE at 15 mmol/L. The results of molecular simulation indicated that NYRRE could insert into the hydrophobic pocket of BSA and interact with hot spots, including arginine and lysine residues. The mechanism of NYRRE inhibiting protein glycation could be due to its antioxidant activity, BSA structure stabilizing ability, and specific bond with glycation sites of BSA. These results provided a valuable reference for developing NYRRE as an efficient antiglycation agent in preventing glycation-mediated diseases.