Detection, Characterization, and Decay Kinetics of ROS and Thiyl Adducts of Mito-DEPMPO Spin Trap

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• 作者：Mica&euml ; l Hardy ; Antal Rockenbauer ; Jeannette Vá ; squez-Vivar ; Christopher Felix ; Marcos Lopez ; Satish Srinivasan ; Narayan Avadhani ; Paul Tordo ; B. Kalyanaraman
• 刊名：Chemical Research in Toxicology
• 出版年：2007
• 出版时间：July 2007
• 年：2007
• 卷：20
• 期：7
• 页码：1053 - 1060
• 全文大小：520K
• 年卷期：v.20,no.7(July 2007)
• ISSN：1520-5010

文摘

We report here the detection and characterization of spin adducts formed from the trapping of reactiveoxygen species (superoxide and hydroxyl radicals) and glutathiyl and carbon-centered radicals by a newlysynthesized nitrone, Mito-DEPMPO. This is a cationic nitrone spin trap with a triphenyl phosphoniumcation conjugated to the DEPMPO analogue. The Mito-DEPMPO-OOH adduct, formed from the trappingof superoxide by Mito-DEPMPO, was enzymatically generated using xanthine/xanthine oxidase andneuronal nitric oxide synthase, and chemically generated by KO₂ in 18-crown-6. The Mito-DEPMPO-OOH adduct exhibits an eight-line EPR spectrum with partial asymmetry arising from the alternate line-width effect. The half-life of the Mito-DEPMPO-OOH adduct is 2-2.5-times greater than that of theDEPMPO-OOH. The Mito-DEPMPO-SG adduct, formed from the trapping of glutathiyl radicals by Mito-DEPMPO, is 3-times more persistent than the analogue DEPMPO-SG adduct. In this study, we describethe EPR characterization of spin adducts formed from Mito-DEPMPO. The EPR parameters of Mito-DEPMPO adducts are distinctly different and highly characteristic. The detection of superoxide from anintact mitochondrion was feasible with Mito-DEPMPO but not with DEPMPO. We conclude that Mito-DEPMPO nitrone and its analogues are more effective than most nitrone spin traps for trapping superoxide,hydroxyl, and thiyl radicals formed in biological systems, including mitochondria.