黑暗中双氧的产生：氧阴离子的歧化酶
Production of dioxygen in the dark: dismutases of oxyanions.
作者信息
DuBois Jennifer L, Ojha Sunil
机构信息
Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA,
出版信息
Met Ions Life Sci. 2015;15:45-87. doi: 10.1007/978-3-319-12415-5_3.
O₂-generating reactions are exceedingly rare in biology and difficult to mimic synthetically. Perchlorate-respiring bacteria enzymatically detoxify chlorite (ClO₂(-) ), the end product of the perchlorate (ClO(4)(-) ) respiratory pathway, by rapidly converting it to dioxygen (O₂) and chloride (Cl(-)). This reaction is catalyzed by a heme-containing protein, called chlorite dismutase (Cld), which bears no structural or sequence relationships with known peroxidases or other heme proteins and is part of a large family of proteins with more than one biochemical function. The original assumptions from the 1990s that perchlorate is not a natural product and that perchlorate respiration might be confined to a taxonomically narrow group of species have been called into question, as have the roles of perchlorate respiration and Cld-mediated reactions in the global biogeochemical cycle of chlorine. In this chapter, the chemistry and biochemistry of Cld-mediated O₂generation, as well as the biological and geochemical context of this extraordinary reaction, are described.
在生物学中，产生氧气的反应极为罕见，且难以通过合成来模拟。利用高氯酸盐呼吸的细菌会通过酶将亚氯酸盐（ClO₂⁻）——高氯酸盐（ClO₄⁻）呼吸途径的终产物——快速转化为氧气（O₂）和氯离子（Cl⁻），从而对其进行解毒。该反应由一种含血红素的蛋白质催化，这种蛋白质称为亚氯酸盐歧化酶（Cld），它与已知的过氧化物酶或其他血红素蛋白在结构或序列上均无关联，并且是一个具有多种生化功能的蛋白质大家族的一部分。20世纪90年代的最初假设认为高氯酸盐不是天然产物，且高氯酸盐呼吸可能仅限于分类学上范围狭窄的一组物种，如今这些假设已受到质疑，高氯酸盐呼吸和Cld介导的反应在全球氯生物地球化学循环中的作用也受到了质疑。在本章中，将描述Cld介导的氧气生成的化学和生物化学，以及这一非凡反应的生物学和地球化学背景。
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