Magalon Axel, Mendel Ralf R
EcoSal Plus. 2015;6(2). doi: 10.1128/ecosalplus.ESP-0006-2013.
The transition element molybdenum (Mo) is of primordial importance for biological systems, because it is required by enzymes catalyzing key reactions in the global carbon, sulfur, and nitrogen metabolism. To gain biological activity, Mo has to be complexed by a special cofactor. With the exception of bacterial nitrogenase, all Mo-dependent enzymes contain a unique pyranopterin-based cofactor coordinating a Mo atom at their catalytic site. Various types of reactions are catalyzed by Mo-enzymes in prokaryotes including oxygen atom transfer, sulfur or proton transfer, hydroxylation, or even nonredox reactions. Mo-enzymes are widespread in prokaryotes and many of them were likely present in the Last Universal Common Ancestor. To date, more than 50--mostly bacterial--Mo-enzymes are described in nature. In a few eubacteria and in many archaea, Mo is replaced by tungsten bound to the same unique pyranopterin. How Mo-cofactor is synthesized in bacteria is reviewed as well as the way until its insertion into apo-Mo-enzymes.
过渡元素钼（Mo）对生物系统至关重要，因为催化全球碳、硫和氮代谢中关键反应的酶需要它。为了获得生物活性，钼必须与一种特殊的辅因子结合。除了细菌固氮酶外，所有依赖钼的酶都含有一种独特的基于吡喃蝶呤的辅因子，该辅因子在其催化位点配位一个钼原子。原核生物中的钼酶催化各种类型的反应，包括氧原子转移、硫或质子转移、羟基化，甚至非氧化还原反应。钼酶在原核生物中广泛存在，其中许多可能存在于最后的共同祖先中。迄今为止，自然界中已描述了50多种（大多是细菌的）钼酶。在一些真细菌和许多古细菌中，钼被与相同独特吡喃蝶呤结合的钨所取代。本文综述了细菌中钼辅因子的合成方式以及直至其插入脱辅基钼酶的过程。
