What are the classifications of oxidoreductases?

Oxidoreductases make up a significant enzyme class categorized as EC 1 in the Enzyme Commission (EC) number classification system. They encompass various subclasses (totaling 22 distinctive groups). Each subclass carries out distinct roles in catalyzing oxidation-reduction reactions in biological processes. These enzymes, comprising oxidases and dehydrogenases, participate in vital metabolic activities. 

Oxidases are enzymes involved when molecular oxygen functions as a recipient of either hydrogen or electrons during the oxidation process. On the other hand, dehydrogenases are enzymes which facilitate oxidation by transferring hydrogen from a substrate to an acceptor (such as NAD+ / NADP+ or a flavin enzyme). In addition to oxidases and dehydrogenases, peroxidases, hydroxylases, oxygenases, and reductases also belong to the oxidoreductase class. Peroxidases, typically located in peroxisomes, play a role in catalyzing the reduction of hydrogen peroxide. Hydroxylases introduce hydroxyl groups to substrates, whereas oxygenases incorporate oxygen from molecular oxygen into organic compounds. Reductases, in many instances, can exhibit oxidase-like functions, although their primary role lies in facilitating reductions in various biochemical reactions. The comprehensive EC number classification displays the diverse nature of these enzymes in catalyzing oxidation-reduction reactions throughout numerous metabolic pathways in organisms.