ESR evidence for superoxide, hydroxyl radicals and singlet oxygen produced from hydrogen peroxide and nickel(II) complex of glycylglycyl-L-histidine.
ESR studies using spin traps, 5,5-dimethylpyrroline-N-oxide and alpha-(4-pyridyl 1-oxide)-N-tert-butylnitrone, revealed that hydroxyl radical adducts are produced by the decomposition of hydrogen peroxide in the presence of nickel(II) oligopeptides. Order of catalytic activities of nickel(II) oligopeptides used in the production of hydroxyl radical adducts was tetraglycine greater than pentaglycine greater than triglycine greater than GlyGly, GlyHis. Ni(II) GlyGlyHis plus hydrogen peroxide produced superoxide in addition to hydroxyl radical adduct. Trapping experiments with 2,2,6,6-tetramethyl-4-piperidone suggested that singlet oxygen was generated by the reaction of hydrogen peroxide with Ni(II) GlyGlyHis, but not in the case of tetraglycine, pentaglycine, triglycine, GlyGly or GlyHis.
Inoue
S
S
Department of Public Health, Faculty of Medicine, Kyoto University, Japan.
Kawanishi
S
S
D002384:Catalysis; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals; D006861:Hydrogen Peroxide; D006878:Hydroxides; D017665:Hydroxyl Radical; D009532:Nickel; D009842:Oligopeptides; D010100:Oxygen; D013113:Spin Labels; D013481:Superoxides
D005609:Free Radicals; D006878:Hydroxides; D009842:Oligopeptides; D013113:Spin Labels; D013481:Superoxides; D017665:Hydroxyl Radical; D009532:Nickel; D006861:Hydrogen Peroxide; D010100:Oxygen