O2- generation and lipid peroxidation during the oxidation of a glycated polypeptide, glycated polylysine, in the presence of iron-ADP.
Oxidation of glycated polylysine, a model compound of glycated protein, caused O2- production even at physiological pH, which could be accelerated by Fe3(+)-ADP. An enediol structure in glycated polylysine and related compounds, which could be confirmed by I2 uptake, was related to their oxidizability. Glycated polylysine was easily coordinated with Fe3+ even in the presence of phosphate at pH 7.4 and the formation of the iron complex was prevented by desferrioxamine. The exposure of unsaturated phospholipid liposomes to glycated polylysine-Fe3(+)-ADP system caused the production of a thiobarbituric acid-reacting substance, which was completely inhibited by 5 microM alpha-tocopherol or 150 microM desferrioxamine and slightly by 0.5 microM SOD. Catalase (20 micrograms/ml) and 10 mM sodium-benzoate did not affect the iron-glycated polylysine-induced lipid peroxidation, indicating no participation of an OH. in this reaction. A ferrous ion-coordinated glycated polylysine may act as an initiator of phospholipid peroxidation in the presence of oxygen. A possible mechanism of the iron-glycated polylysine-induced lipid peroxidation was discussed.
Sakurai
T
T
Tokyo College of Pharmacy, Japan.
Sugioka
K
K
Nakano
M
M
D000244:Adenosine Diphosphate / Q000494:pharmacology*; D003676:Deferoxamine / Q000494:pharmacology; D005290:Ferric Compounds / Q000494:pharmacology; D006031:Glycosylation; D006863:Hydrogen-Ion Concentration; D007455:Iodine / Q000378:metabolism; D007501:Iron / Q000494:pharmacology*; D015227:Lipid Peroxidation; D008081:Liposomes / Q000378:metabolism; D008163:Luminescent Measurements; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D011107:Polylysine / Q000378:metabolism*; D013053:Spectrophotometry; D013482:Superoxide Dismutase / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism*; D013858:Thiobarbiturates; D014810:Vitamin E / Q000494:pharmacology
D005290:Ferric Compounds; D008081:Liposomes; D013858:Thiobarbiturates; D013481:Superoxides; D014810:Vitamin E; D011107:Polylysine; D000244:Adenosine Diphosphate; D007455:Iodine; D007501:Iron; D013482:Superoxide Dismutase; D003676:Deferoxamine; C029684:thiobarbituric acid