Transition metal-mediated glycoxidation accelerates cross-linking of beta-amyloid peptide

beta-Amyloid deposits, hallmarks of Alzheimer's disease, contain both sugar -derived 'advanced glycation end products' (AGEs) and copper and iron ions. Our in vitro experiments using synthetic beta-amyloid peptide and glucose or fructose show that formation of covalently cross-linked high-molecular-m ass beta-amyloid peptide oligomers is accelerated by micromolar amounts of copper (Cu+, Cu2+) and iron (Fe2+, Fe3+) ions. Formation of these covalent AGE cross-links can be inhibited by capping agents of amino groups, redox-i nactive metal chelators and antioxidants, suggesting that these drugs may b e able to slow down the formation of insoluble beta-amyloid deposits in viv o and possibly the progression of Alzheimer's disease.