Liochev S I, Hausladen A, Beyer W F, Fridovich I
Department of Biochemistry, Duke University Medical Center, Durham, NC 27710.
Proc Natl Acad Sci U S A. 1994 Feb 15;91(4):1328-31. doi: 10.1073/pnas.91.4.1328.
Soluble extracts of Escherichia coli contain four NADPH:paraquat diaphorases that were separable by anion-exchange HPLC over Mono Q. One of these was induced when the cells were exposed to paraquat. This was the case in a soxRS-competent strain but not in a soxRS-null strain, while a soxRS-constitutive strain overexpressed this diaphorase without the stimulus of exposure to paraquat. This NADPH:paraquat diaphorase could use cytochrome c or nitroblue tetrazolium as an electron acceptor, whereas O2 was a relatively poor acceptor. This diaphorase was identified as the NADPH:ferredoxin reductase. A role for reduced ferredoxin and flavodoxin in the adaptive soxRS response to oxidative stress and in the regulation of the redox status of soxR is discussed.
大肠杆菌的可溶性提取物含有四种NADPH：百草枯双加氧酶，可通过在Mono Q上进行阴离子交换高效液相色谱分离。其中一种在细胞暴露于百草枯时被诱导产生。在具有功能性soxRS的菌株中是这种情况，但在soxRS缺失的菌株中则不是，而一个组成型soxRS菌株在没有百草枯暴露刺激的情况下过表达这种双加氧酶。这种NADPH：百草枯双加氧酶可以使用细胞色素c或硝基蓝四氮唑作为电子受体，而O2是相对较差的受体。这种双加氧酶被鉴定为NADPH：铁氧还蛋白还原酶。讨论了还原型铁氧还蛋白和黄素氧还蛋白在适应性soxRS对氧化应激的反应以及soxR氧化还原状态调节中的作用。
