Mechanistic Studies of the Reactions of Nitrone Spin Trap PBN with Glutathiyl Radical
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- 作者：Dmitriy N. Polovyanenko ; Victor F. Plyusnin ; Vladimir A. Reznikov ; Valery V. Khramtsov ; Elena G. Bagryanskaya
- 刊名：Journal of Physical Chemistry B
- 出版年：2008
- 出版时间：April 17, 2008
- 年：2008
- 卷：112
- 期：15
- 页码：4841 - 4847
- 全文大小：130K
- 年卷期：v.112,no.15(April 17, 2008)
- ISSN：1520-5207
文摘
We performed mechanistic studies of the reaction of PBN with the physiologically relevant glutathiyl radical,GS
, formed upon oxidation of the intracellular antioxidant, glutathione, GSH. The scavenging rate constantof GS by PBN has been measured directly by laser flash photolysis and indirectly by competitive EPR of thespin adduct of PBN and another spin trap, DMPO (5,5-dimethyl-1-pyrroline N-oxide), and was found to be6.7 × 107 M-1 s-1. Reverse decomposition of the paramagnetic PBN-glutathiyl radical adduct to the nitroneand thiyl radical was observed for the first time. The rate constant for the reaction of the monomoleculardecomposition of the radical adduct was found to be 1.7 s-1. Diamagnetic, EPR-invisible products of PBNadduct degradation were studied by 1H NMR and 19F NMR using newly synthesized fluorine-substitutedPBN.
, formed upon oxidation of the intracellular antioxidant, glutathione, GSH. The scavenging rate constantof GS by PBN has been measured directly by laser flash photolysis and indirectly by competitive EPR of thespin adduct of PBN and another spin trap, DMPO (5,5-dimethyl-1-pyrroline N-oxide), and was found to be6.7 × 107 M-1 s-1. Reverse decomposition of the paramagnetic PBN-glutathiyl radical adduct to the nitroneand thiyl radical was observed for the first time. The rate constant for the reaction of the monomoleculardecomposition of the radical adduct was found to be 1.7 s-1. Diamagnetic, EPR-invisible products of PBNadduct degradation were studied by 1H NMR and 19F NMR using newly synthesized fluorine-substitutedPBN.