Oxidoreductases (EC 1)

Enzymes can be classified systematically according to the difference between reaction and substrate specificity, and the mechanism of action. Oxidoreductases (EC 1.x.x.x) are the first enzyme class in the Enzyme Commission Nomenclature. Oxidoreductases are a large group of enzymes that catalyze the transfer of electrons from one molecule (the oxidant, the hydrogen or the electron donor) to another molecule (the reductant, the hydrogen or electron acceptor). In other words, oxidoreductases catalyze oxidoreduction reactions that occur within the cell, includes oxidase, oxygenase, peroxidase, dehydrogenase, and others. However, it often needs cofactors such as nicotinamide adenine dinucleotides (e.g., NAD+/NADH) and flavines (e.g., FAD/FADH2) in the reactions. Oxidoreductases are a fundamental class of enzymes responsible for the catalysis of oxidation-reduction reactions, crucial in most bioenergetic metabolic pathways.