SPIN TRAP STUDIES ON THE DECOMPOSITION OF PEROXYNITRITE
SPIN TRAP STUDIES ON THE DECOMPOSITION OF PEROXYNITRITE
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DOI：
10.1006/abbi.1995.1364
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发表时间：
1995-08-01
影响因子：
3.9
通讯作者：
PRYOR, WA
中科院分区：
文献类型：
--
作者：
LEMERCIER, JN;SQUADRITO, GL;PRYOR, WA
本文用5，5-二甲基-1-吡咯啉-N-氧化物（DMPO）的羟基自由基自旋加合物作为过亚硝酸根分解产生羟基自由基的探针。当过氧亚硝酸盐在DMPO存在下分解时，观察到自由基（DMPO-OH），得出的结论是，这并不构成存在自由羟基自由基的证据。过亚硝酸根的衰变速率常数从0.35增加到0.51 s（-1）当DMPO的浓度从0增加到75 mM时（增加46%）。这强烈地表明DMPO和HOONO之间或DMPO和HOONO的活化中间体之间存在反应，以产生羟基自由基自旋加合物，谷胱甘肽或半胱氨酸的加入使（.）DMPO-OH自旋加合物信号;采用超氧化物歧化酶的实验表明，（.）DMPO-OH加合物是由超氧自由基（（.）DMPO-OOH）。超氧化物加合物是硫醇自氧化的结果，这是一种已知的产生超氧化物的过程。这里提出的结果是不相容的自由羟基自由基的形成，但可以解释在HOONO的中间体，这是反应性较低，比自由羟基自由基的选择性更高。(C)出版社：Academic Press
The observation of the hydroxyl radical spin adduct of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) is evaluated as a probe for the production of hydroxyl radicals from the decomposition of peroxynitrite, Although a weak signal corresponding to the DMPO-hydroxyl radical spin adduct ((.)DMPO-OH) is observed when peroxynitrite is allowed to decompose in the presence of DMPO, it is concluded that this does not constitute proof of the presence of free hydroxyl radicals. The observed rate constant for the decay of peroxynitrite increases from 0.35 to 0.51 s(-1) (46% increase) when the concentration of DMPO is increased from 0 to 75 mM. This strongly suggests there is a reaction between DMPO and HOONO, or between DMPO and an activated intermediate of HOONO, to produce the hydroxyl radical spin adduct, The addition of glutathione or cysteine produces a large increase in the intensity of the (.)DMPO-OH spin adduct signal; experiments employing superoxide dismutase suggest that the increases in the amounts of (.)DMPO-OH adduct are produced from the decomposition of the spin adduct of the superoxide radical ((.)DMPO-OOH). The superoxide adduct arises as a result of the autoxidation of thiols, a process known to produce superoxide. The results presented here are incompatible with the formation of free hydroxyl radicals but can be explained in terms of an intermediate of HOONO that is less reactive and more selective than the free hydroxyl radical. (C) 1995 Academic Press, Inc.