人过氧化物还原酶3的氧化还原电位和过氧化物反应活性

Redox potential and peroxide reactivity of human peroxiredoxin 3.

作者信息

Cox Andrew G, Peskin Alexander V, Paton Louise N, Winterbourn Christine C, Hampton Mark B

机构信息

Free Radical Research Group and National Research Centre for Growth and Development, Department of Pathology, University of Otago, Christchurch, New Zealand.

出版信息

Biochemistry. 2009 Jul 14;48(27):6495-501. doi: 10.1021/bi900558g.

DOI:10.1021/bi900558g

PMID:19462976

Abstract

Peroxiredoxins (Prxs) are a ubiquitous family of thiol peroxidases that protect cells from peroxides and have a putative role in redox signaling. In this study, we investigated the redox properties of human Prx 3, a typical 2-Cys Prx that is localized to the mitochondrial matrix. We found that Prx 3 displayed strong reactivity with H(2)O(2), with a competitive kinetic approach generating a second order rate constant of 2 x 10(7) M(-1) s(-1). This is considerably higher than typical thiols and similar to values for other mammalian 2-Cys Prxs. In contrast, Prx 3 reacted very slowly with the thiol alkylating agents iodoacetamide and N-ethylmaleimide. Using dithiothreitol redox buffers, we measured the redox potential of Prx 3 of -290 mV. This is similar to the redox potential of mitochondrial thioredoxin 2 and is consistent with optimal operation of Prx 3 in the mitochondrial matrix.

摘要

过氧化物酶（Prxs）是一类普遍存在的硫醇过氧化物酶家族，可保护细胞免受过氧化物的侵害，并在氧化还原信号传导中发挥推定作用。在本研究中，我们研究了人Prx 3的氧化还原特性，Prx 3是一种定位于线粒体基质的典型2-半胱氨酸Prx。我们发现Prx 3与H₂O₂表现出很强的反应性，采用竞争动力学方法得出的二级速率常数为2×10⁷ M⁻¹ s⁻¹。这大大高于典型硫醇，与其他哺乳动物2-半胱氨酸Prx的值相似。相比之下，Prx 3与硫醇烷基化剂碘乙酰胺和N-乙基马来酰亚胺的反应非常缓慢。使用二硫苏糖醇氧化还原缓冲液，我们测得Prx 3的氧化还原电位为-290 mV。这与线粒体硫氧还蛋白2的氧化还原电位相似，并且与Prx 3在线粒体基质中的最佳运作一致。