The fidelity of spin trapping with DMPO in biological systems.
The fidelity of spin trapping with DMPO in biological systems.
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DOI：
10.1002/mrc.2709
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发表时间：
2011-04
影响因子：
2
通讯作者：
Mason, Ronald P.
中科院分区：
文献类型：
--
作者：
Ranguelova, Kalina;Mason, Ronald P.
与直接ESR不同，自旋陷阱方法依赖于自旋陷阱反应的绝对保真度。发现并研究了5，5-二甲基-1-吡咯啉N-氧化物(DMPO)导致自由基加合物伪影的两个替代反应：倒转自旋捕获和Forrester-Hepburn亲核机理。这两条生成自由基加合物的交替途径是单电子氧化和亲核加成的组合。在生物系统中，由于Forrester-Hepburn机制，已经报道了严重的伪影，该机制是由DMPO中添加的亲核试剂启动的。最近的研究表明，(双)亚硫酸盐(水合二氧化硫)可以通过非自由基的亲核反应与DMPO反应，并进一步提出生物体系中DMPO/·SO3−的形成是一种人工产物，而不是三氧化硫阴离子自由基(·SO3−)自旋捕获的结果。用DMPO的ESR自旋捕捉和氧吸收研究了辣根过氧化物酶(HRP)/过氧化氢(H_2O_2)催化(Bi)亚硫酸盐的单电子氧化反应，为自由基反应机理提供了进一步证据。在没有DMPO的情况下，(Bi)亚硫酸盐依赖的氧和H_2O_2消耗的初始速率是ESR测定的DMPO/·SO_3−自由基加合物形成初始速率的一半，表明在我们的实验条件下，DMPO是通过捕获·SO_3−来形成自由基加合物的。
Unlike direct ESR, spin trap methodology depends on the absolute fidelity of the spin trap reaction. Two alternative reactions of 5,5-dimethyl-1-pyrroline N-oxide (DMPO) leading to radical adduct artifacts have been discovered and investigated: inverted spin trapping and the Forrester-Hepburn nucleophilic mechanisms. These two alternate pathways to radical adducts are a combination of one-electron oxidation and nucleophilic addition, in either order. In biological systems, serious artifacts have been reported due to the Forrester-Hepburn mechanism, which is initiated by the addition of a nucleophile to DMPO. It has recently been demonstrated that (bi)sulfite (hydrated sulfur dioxide) can react with DMPO via a nonradical, nucleophilic reaction, and it has been further proposed that DMPO/•SO3− formation in biological systems is an artifact and not the result of spin trapping of sulfur trioxide anion radical (•SO3−). The one-electron oxidation of (bi)sulfite catalyzed by horseradish peroxidase (HRP)/hydrogen peroxide (H2O2) has been reinvestigated by ESR spin trapping with DMPO and oxygen uptake studies to obtain further evidence for the radical reaction mechanism. In the absence of DMPO, the initial rate of (bi)sulfite-dependent oxygen and H2O2 consumption was determined to be half of the initial rate of DMPO/•SO3− radical adduct formation as determined by ESR, demonstrating that, under our experimental conditions, DMPO exclusively forms the radical adduct by trapping the •SO3−.
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DOI：
10.1039/p29960002631
发表时间：
1996-12-01
期刊：
JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2
影响因子：
--
作者：
Bhattacharjee, S;Khan, MN;Symons, MCR
通讯作者：
Symons, MCR
DOI：
10.1039/c39860001301
发表时间：
1986-08-15
影响因子：
--
作者：
CHANDRA, H;SYMONS, MCR
通讯作者：
SYMONS, MCR
DOI：
10.1039/p29940000171
发表时间：
1994-02-01
期刊：
JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2
影响因子：
--
作者：
EBERSON, L
通讯作者：
EBERSON, L
影响因子：
5
作者：
Brandt, C;Elding, LI
通讯作者：
Elding, LI
影响因子：
3.6
作者：
CERRI, V;FREJAVILLE, C;TORDO, P
通讯作者：
TORDO, P