Formation of superoxide anion during ferrous ion-induced decomposition of linoleic acid hydroperoxide under aerobic conditions.
We studied the mechanism of formation of oxygen radicals during ferrous ion-induced decomposition of linoleic acid hydroperoxide using the spin trapping and chemiluminescence methods. The formation of the superoxide anion (O2*-) was verified in the present study. The hydroxyl radical is also generated through Fenton type decomposition of hydrogen peroxide produced on disproportionation of O2*-. A carbon-centered radical was detected using 5-(diethoxyphosphoryl)-5-methyl-1-pyrroline N-oxide (DEPMPO) as a spin trap. Alkoxyl radical formation is essential for the conversion of linoleic acid hydroperoxide into the peroxyl radical by ferrous ion. It is likely that the alkoxyl radical [R1CH(O*)R2] is converted into the hydroxylcarbon radical [R1C*(OH)R2] in water, and that this carbon radical reacts with oxygen to give the alpha-hydroxyperoxyl radical [R1R2C(OH)OO*], which decomposes into the carbocation [R1C+(OH)R2] and O2*-.
Kambayashi
Yasuhiro
Y
Department of Photon and Free Radical Research, Japan Immunoresearch Laboratories, 351-1 Nishiyokote-cho, Takasaki 370-0021. kambayashi@pub.m.kanazawa-u.ac.jp
Tero-Kubota
Shozo
S
Yamamoto
Yorihiro
Y
Kato
Masashi
M
Nakano
Minoru
M
Yagi
Kunio
K
Ogino
Keiki
K
D000332:Aerobiosis; D001128:Argon / Q000737:chemistry; D002384:Catalysis; D003497:Cyclic N-Oxides / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D005296:Ferrous Compounds / Q000737:chemistry*; D005609:Free Radicals / Q000737:chemistry; D008041:Linoleic Acids / Q000737:chemistry / Q000378:metabolism*; D008054:Lipid Peroxides / Q000737:chemistry / Q000378:metabolism*; D008163:Luminescent Measurements; D013113:Spin Labels; D019097:Spin Trapping; D013481:Superoxides / Q000737:chemistry* / Q000378:metabolism*
D003497:Cyclic N-Oxides; D005296:Ferrous Compounds; D005609:Free Radicals; D008041:Linoleic Acids; D008054:Lipid Peroxides; D013113:Spin Labels; D013481:Superoxides; C008285:linoleic acid hydroperoxide; D001128:Argon; C017245:5,5-dimethyl-1-pyrroline-1-oxide