Construction of cell-free anammox reaction system

本研究参照已有的厌氧氨氧化机理模型，构建无细胞厌氧反应体系。得到了以下对系统构建的重要发现。(1)用异二聚体血红素蛋白NaxLS催化肼合酶以NO和NH4+为原料合成肼。(2)虽然细胞色素cd1 Nir仅在其他厌氧氨氧化菌中存在，但在菌株KSU-1中，Cu-Nir合成了中间产物NO。(3)一种多血红素蛋白羟胺氧化还原酶（hydroxylamine oxidoreductase， HAO）催化NO与羟胺的相互转化。

This study was performed to construct cell-free anaerobic reaction system by reference to the previously described model for mechanism of anammox. The following important findings for construction of the system were obtained. (1) Hydrazine was synthesized from NO and NH4+ catalyzed by hydrazine synthase with a heterodimer heme protein, NaxLS. (2) An intermediate, NO, was synthesized by Cu-type nitrite reductase (Cu-Nir) in strain KSU-1 although cytochrome cd1 Nir has only been known in other anammox bacteria. (3) A multiheme protein, hydroxylamine oxidoreductase (HAO), catalyzed inter-conversion of NO and hydroxylamine.