@article{oai:repo.qst.go.jp:00043083,
 author = {Takeshita, Keizo and Saito, Keita and Ueda, Junichi and Anzai, Kazunori and Ozawa, Toshihiko and 竹下 啓蔵 and 齋藤 圭太 and 上田 順市 and 安西 和紀 and 小澤 俊彦},
 journal = {Biochimica et Biophysica Acta. General Subjects},
 month = {},
 note = {The effect of the chemical structure of nitroxyl spin probes on the rate at which ESR signals are lost in the presence of reactive oxygen species was examined.  When the spin probes were reacted with either hydroxyl radical (.OH) or superoxide anion radical (O2.-) in the presence of cysteine or NADH, the probes lost ESR signal depending on both their ring structure and substituents.  Pyrrolidine nitroxyl probes were relatively resistant to the signal decay caused by O2.- with cysteine/NADH.  Signal decay rates for these reactions correlated with reported redox potentials of the nitroxyl/oxoammonium couple of spin probes, suggesting that the signal decay mechanism in both cases involves the oxidation of a nitroxyl group.  The apparent rate constants of the reactions between the spin probe and .OH and between the spin probe and O2.- in the presence of cysteine were estimated using mannitol and superoxide dismutase, respectively, as competitive standards.  The rate constants for spin probes and .OH were in the order of 109 M-1s-1, much higher than those for the probes and O2.- in the presence of cysteine (103-104 M-1s-1).  These basic data are useful for the measurement of .OH and O2.- in living animals by in vivo ESR spectroscopy.},
 pages = {156--164},
 title = {Kinetic Study on ESR signal decay of nitroxyl radicals, potent redox probes for in vivo ESR spectroscopy, caused by reactive oxygen species},
 volume = {1573},
 year = {2002}
}