The operation of the alternative electron-leak pathways mediated by cytochrome c in mitochondria

被引:26
作者
Zhao, YG [1 ]
Xu, HX [1 ]
机构
[1] Chinese Acad Sci, Inst Biophys, Beijing 100101, Peoples R China
关键词
cytochrome c; hydrogen peroxide; hydroxyl radical; electron transfer; alternative electron-leak pathway;
D O I
10.1016/j.bbrc.2004.03.144
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Low (1 x 10(-9) M) concentrations of cytochrome c inhibit H2O2 production in cytochrome c-depleted mitochondria, purified succinate-cytochrome c reductase (SCR) and antimycin A inhibited cytochrome c-depleted HMP. At higher concentration (2 x 10(-6)M), cytochrome c eliminates pre-existed H2O2, if feeding electrons to it by succinate. Cytochrome c also decreases the OH-produced by succinate-cytochrome c reductase oxidizing succinate. We conclude that the alternative electron-leak pathway mediated by cytochrome c operates very well. In the presence of antimycin A, ferrocytochrome c can suppress the generation of H2O2 in SCR system, but ferricytochrome c cannot. Similar results are obtained on the elimination of pre-existed H2O2 by cytochrome c. For hydroxyl radical, antimycin A abolishes the suppression caused by both ferrocytochrome c and ferricytochrome c. These results indicate that the reductive state of cytochrome c caused by electron-flow is necessary and sufficient for the operation of cytochrome c-mediated electron-leakage pathway. (C) 2004 Elsevier Inc. All rights reserved.
引用
收藏
页码:980 / 987
页数:8
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