Generation of OH radical during enzymatic reduction of 9,10-anthraquinone-2-sulphonate. Can semiquinone decompose hydrogen peroxide?
Spin-trapping experiments have shown that 9,10-anthraquinone-2-sulphonate (AQS) can be reduced enzymatically with NADPH-cytochrome P-450 reductase (FP) producing OH radicals. It has been revealed for the first time that the radical anion of AQS cannot decompose H2O2 as indicated by flash-photolysis data. From the experimental results obtained it follows that an enzyme system containing NADPH, AQS and FP produces both accumulation of H2O2 from molecular oxygen and reduction of Fe3+ to Fe2+ which decomposes H2O2 catalytically via a Fenton reaction.
Sushkov
D G
DG
Institute of Chemical Kinetics and Combustion, Novosibirsk, USSR.
Gritsan
N P
NP
Weiner
L M
LM
D000880:Anthraquinones / Q000378:metabolism*; D016227:Benzoquinones; D003497:Cyclic N-Oxides; D004578:Electron Spin Resonance Spectroscopy; D006861:Hydrogen Peroxide / Q000378:metabolism*; D006878:Hydroxides / Q000378:metabolism*; D017665:Hydroxyl Radical; D007700:Kinetics; D009249:NADP / Q000378:metabolism; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D010782:Photolysis; D011809:Quinones / Q000378:metabolism*; D013113:Spin Labels
D000880:Anthraquinones; D016227:Benzoquinones; D003497:Cyclic N-Oxides; D006878:Hydroxides; D011809:Quinones; D013113:Spin Labels; C023554:anthraquinone sulfonate; C025232:semiquinone radicals; D017665:Hydroxyl Radical; D009249:NADP; C017245:5,5-dimethyl-1-pyrroline-1-oxide; D006861:Hydrogen Peroxide; D009251:NADPH-Ferrihemoprotein Reductase; D010100:Oxygen