Transition metals bind to glycated proteins forming redox active "glycochelates": Implications for the pathogenesis of certain diabetic complications

The present investigations arose from our interest in the possibility that some structures which arise secondary to protein glycation might bind transition metals such as iron and copper. In support of this we find that, when glycated, three different proteins-albumin, gelatin (a soluble collagen fragment) and elastin-all gain a substantial affinity for the transition metals iron and copper. The glycated proteins bind at least three times as much iron as do the non-glycated proteins. Similarly, glycated albumin and gelatin also bind 2-3 times as much copper. Furthermore, at least in the case of copper bound to glycated albumin, the bound metal retains redox activity and participates in the catalytic oxidation of ascorbic acid. Should similar "glycochelates"' form in vivo in diabetics, reactions mediated by these chelates may be involved in certain complications of diabetes. (C) 1998 Academic Press.