Molybdenum and tungsten enzymes redox properties – A brief overview

Metalloproteins and metal-containing enzymes are well known to be essential to life. Molybdenum and tungsten are the heaviest transition metals used by biology. The mononuclear molybdenum (and tungsten)containing enzymes have in common a particular conserved metal centre (Mo, W)coordinated by one or two pyranopterins. The metal coordination sphere is completed with oxygen and/or sulfur and/or selenium atoms in a diversity of arrangements. The enzymes organized in families (XO, SO and DMSOR)being diverse, can participate in a myriad of reactions involving atom insertion or abstraction and others, with different substrates and partners (physiological or not). The first and second coordination spheres tune the redox properties of the metal centres (and its catalytic features)for a wide range of reactions. In this review, a brief account is given on the main reactions catalysed by this class of enzymes, as well as a representative summary of the redox properties.