Use of M4PO and oxygen-17 in the study on hydroxyl radical generation in the hypoxanthine-xanthine oxidase reaction.
To determine whether hydroxyl radicals (.OH) are generated in the hypoxanthine (HPX)-xanthine oxidase (XOD) reaction, we examined the electron paramagnetic resonance (EPR) spectra of the spin adducts formed. In the EPR study, we used 3,3,5,5-tetramethyl-1-pyrroline-N-oxide (M4PO) as a spin trap, sodium formate (HCOONa) as a .OH scavenger, and oxygen-17 gas as an oxygen source. In the HPX-XOD reaction, both M4PO-OOH and M4PO-OH were observed in the reaction products. The formation of M4PO-OH was independently inhibited by HCOONa resulting in the formation of M4PO-CO2- and in no effects on the formation of M4PO-OOH. With oxygen-17 gas as an oxygen source in the HPX-XOD reaction, both M4PO-17OOH and M4PO-17OH were observed in the reaction products. These results indicate that M4PO-OH is not produced by decomposition of M4PO-OOH and .OH is actually generated during the HPX-XOD reaction.
Department of Anesthesia, Kyoto University Hospital, Japan.
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Mori
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Tsutsui
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D003497:Cyclic N-Oxides; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D016166:Free Radical Scavengers; D017665:Hydroxyl Radical / Q000032:analysis / Q000378:metabolism*; D019271:Hypoxanthine; D007042:Hypoxanthines / Q000378:metabolism*; D007553:Isotope Labeling / Q000379:methods; D007700:Kinetics; D010103:Oxygen Isotopes; D013113:Spin Labels; D014969:Xanthine Oxidase / Q000378:metabolism*
D003497:Cyclic N-Oxides; D016166:Free Radical Scavengers; D007042:Hypoxanthines; D010103:Oxygen Isotopes; D013113:Spin Labels; C051831:3,3,5,5-tetramethyl-1-pyrroline N-oxide; D019271:Hypoxanthine; D017665:Hydroxyl Radical; D014969:Xanthine Oxidase