Cytochrome bd Displays Significant Quinol Peroxidase Activity
Cytochrome bd Displays Significant Quinol Peroxidase Activity
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DOI：
10.1038/srep27631
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发表时间：
2016-06-09
影响因子：
4.6
通讯作者：
de Vries, Simon
中科院分区：
文献类型：
--
作者：
Al-Attar, Sinan;Yu, Yuanjie;de Vries, Simon
细胞色素bd是一种原核生物末端氧化酶，以泛醇为电子供体催化氧还原为水。细胞色素bd是一种三血红素整合膜酶，携带一个低自旋血红素B（558）和两个高自旋血红素：B（595）和d。在这里，我们表明，除了其氧化酶活性，细胞色素bd大肠杆菌是一个真正的醌醇过氧化物酶（QPO），减少过氧化氢水。本研究中所用的高活性纯酶制剂不显示最近报道的E.大肠杆菌细胞色素bd。据我们所知，细胞色素bd是第一个在大肠杆菌中检测到的膜结合醌醇过氧化物酶。杆菌细胞色素bd是一种醌醇过氧化物酶，这一发现可以为它在过氧化氢解毒中的作用提供生化基础，并可以解释文献中报道的频繁发现，即缺乏酶的突变体对过氧化氢的敏感性增加和毒性降低。
Cytochrome bd is a prokaryotic terminal oxidase that catalyses the electrogenic reduction of oxygen to water using ubiquinol as electron donor. Cytochrome bd is a tri-haem integral membrane enzyme carrying a low-spin haem b(558), and two high-spin haems: b(595) and d. Here we show that besides its oxidase activity, cytochrome bd from Escherichia coli is a genuine quinol peroxidase (QPO) that reduces hydrogen peroxide to water. The highly active and pure enzyme preparation used in this study did not display the catalase activity recently reported for E. coli cytochrome bd. To our knowledge, cytochrome bd is the first membrane-bound quinol peroxidase detected in E. coli. The observation that cytochrome bd is a quinol peroxidase, can provide a biochemical basis for its role in detoxification of hydrogen peroxide and may explain the frequent findings reported in the literature that indicate increased sensitivity to hydrogen peroxide and decreased virulence in mutants that lack the enzyme.