Abstract
Recent studies demonstrated N epsilon-(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 formation in 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 H2O2 mediates CML formation from Amadori compounds.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Catalase / pharmacology
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Enzyme-Linked Immunosorbent Assay
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Ferrous Compounds / metabolism
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Glucose / metabolism
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Glycated Serum Albumin
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Glycation End Products, Advanced / immunology
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Glycation End Products, Advanced / metabolism
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Hydrogen Peroxide / metabolism
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Hydrogen Peroxide / pharmacology
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Hydroxyl Radical / metabolism*
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Hydroxyl Radical / pharmacology
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Lysine / analogs & derivatives*
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Lysine / metabolism
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Mannitol / pharmacology
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Reactive Oxygen Species / metabolism
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Schiff Bases / metabolism
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Serum Albumin / analysis
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Serum Albumin / immunology
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Serum Albumin / metabolism*
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Superoxide Dismutase / metabolism
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Superoxide Dismutase / pharmacology
Substances
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Ferrous Compounds
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Glycation End Products, Advanced
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Reactive Oxygen Species
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Schiff Bases
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Serum Albumin
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Hydroxyl Radical
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Mannitol
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N(6)-carboxymethyllysine
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Hydrogen Peroxide
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Catalase
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Superoxide Dismutase
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Glucose
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Lysine
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ferrous chloride
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Glycated Serum Albumin