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Hydroxyl Radical Mediates Nϵ-(Carboxymethyl)lysine Formation from Amadori Product

1997; Elsevier BV; Volume: 234; Issue: 1 Linguagem: Inglês

10.1006/bbrc.1997.6608

1090-2104

Ryoji Nagai, Kazuyoshi Ikeda, Takayuki Higashi, Hiroyuki Sano, Yoshiteru Jinnouchi, Tomohiro Araki, Seikoh Horiuchi,

Protein Interaction Studies and Fluorescence Analysis

Recent studies demonstrated Nϵ-(carboxymethyl) lysine (CML) in several tissue proteins. Incubation of proteins with glucose leads through a Schiff base to Amadori products. Oxidative cleavage of Amadori products is considered as a major route to CML formationin vivo,whereas it is not known which reactive oxygen species (ROS) is involved. The present study is undertaken to identify such a ROS. We prepared heavily glycated human serum albumin (HSA) which contained a high level of Amadori products, but an undetectable level of CML. Incubation of glycated HSA with FeCl2, but not with H2O2, led to CML formation which was enhanced by H2O2, but inhibited by catalase or mannitol, whereas superoxide dismutase had no effect. Similar data were obtained by experiments using Boc-fructose-lysine as a model Amadori compound. These data indicate that hydroxyl radical generated by the reaction of Fe2+with H2O2mediates CML formation from Amadori compounds.