Reduction of nitric oxide catalyzed by hydroxylamine oxidoreductase from an anammox bacterium
Reduction of nitric oxide catalyzed by hydroxylamine oxidoreductase from an anammox bacterium
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DOI：
10.1016/j.jbiosc.2014.05.018
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发表时间：
2014-12-01
影响因子：
2.8
通讯作者：
Fujii, Takao
中科院分区：
文献类型：
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作者：
Irisa, Tatsuya;Hira, Daisuke;Fujii, Takao
来自厌氧氨氧化菌（Anammox bacterium）的羟胺氧化还原酶（HAO）能催化牛细胞色素c氧化羟胺（NH_2OH）生成一氧化氮（NO）。与此相反，我们研究了来自厌氧氨氧化细菌菌株KSU-1的HAO是否可以催化还原苄基紫精（BVred）和NO释放试剂NOC 7还原NO。进行还原，导致形成作为产物的NH 2 OH。在每个实验中，BVred的氧化速率在短时间内与BVred本身的浓度成正比，这种情况被称为准稳态。在不同浓度的HAO状态的分析，使我们能够确定催化反应的速率常数，（2.85 +/- 0.19）× 10（5）M-1 s（-1），控制NO还原BVred和HAO，这是从铵氧化剂，亚硝化单胞菌与还原甲基紫精的HAO报告的。这些结果表明，anammox HAO的功能，通过相互转换的NO和NH 2 OH依赖于在anammox细菌的生理电子传递蛋白的氧化还原电位来调节anammox。(C)2014年，生物技术学会，日本。All rights reserved.
The hydroxylamine oxidoreductase (HAO) from the anammox bacterium, Candidatus Kuenenia stuttgartiensis has been reported to catalyze the oxidation of hydroxylamine (NH2OH) to nitric oxide (NO) by using bovine cytochrome c as an oxidant. In contrast, we investigated whether the HAO from anammox bacterium strain KSU-1 could catalyze the reduction of NO with reduced benzyl viologen (BVred) and the NO-releasing reagent, NOC 7. The reduction proceeded, resulting in the formation of NH2OH as a product. The oxidation rate of BVred was proportional to the concentration of BVred itself for a short period in each experiment, a situation that was termed quasi-steady state. The analyses of the states at various concentrations of HAO allowed us to determine the rate constant for the catalytic reaction, (2.85 +/- 0.19) x 10(5) M-1 s(-1), governing NO reduction by BVred and HAO, which was comparable to that reported for the HAO from the ammonium oxidizer, Nitrosomonas with reduced methyl viologen. These results suggest that the anammox HAO functions to adjust anammox by inter-conversion of NO and NH2OH depending on the redox potential of the physiological electron transfer protein in anammox bacteria. (C) 2014, The Society for Biotechnology, Japan. All rights reserved.