Mihasan Marius, Chiribau Calin-Bogdan, Friedrich Thorsten, Artenie Vlad, Brandsch Roderich
Institute of Biochemistry and Molecular Biology, Hermann-Herder-Str 7, 79104 Freiburg, Germany.
Appl Environ Microbiol. 2007 Apr;73(8):2479-85. doi: 10.1128/AEM.02668-06. Epub 2007 Feb 9.
An NAD(P)H-nicotine blue (quinone) oxidoreductase was discovered as a member of the nicotine catabolic pathway of Arthrobacter nicotinovorans. Transcriptional analysis and electromobility shift assays showed that the enzyme gene was expressed in a nicotine-dependent manner under the control of the transcriptional activator PmfR and thus was part of the nicotine regulon of A. nicotinovorans. The flavin mononucleotide-containing enzyme uses NADH and, with lower efficiency, NADPH to reduce, by a two-electron transfer, nicotine blue to the nicotine blue leuco form (hydroquinone). Besides nicotine blue, several other quinones were reduced by the enzyme. The NAD(P)H-nicotine blue oxidoreductase may prevent intracellular one-electron reductions of nicotine blue which may lead to semiquinone radicals and potentially toxic reactive oxygen species.
一种NAD(P)H-烟碱蓝（醌）氧化还原酶作为嗜烟节杆菌烟碱分解代谢途径的成员被发现。转录分析和电泳迁移率变动分析表明，该酶基因在转录激活因子PmfR的控制下以烟碱依赖的方式表达，因此是嗜烟节杆菌烟碱调节子的一部分。这种含黄素单核苷酸的酶利用NADH，并以较低效率利用NADPH，通过双电子转移将烟碱蓝还原为烟碱蓝隐色体形式（对苯二酚）。除了烟碱蓝，该酶还能还原其他几种醌。NAD(P)H-烟碱蓝氧化还原酶可能会阻止烟碱蓝在细胞内的单电子还原，而这种还原可能会导致半醌自由基和潜在有毒的活性氧物种。
