In biochemistry, an oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule, the reductant, also called the electron donor, to another, the oxidant, also called the electron acceptor.
This group of enzymes usually utilizes NADP+ or NAD+ as cofactors.
[1][2] Transmembrane oxidoreductases create electron transport chains in bacteria, chloroplasts and mitochondria, including respiratory complexes I, II and III.
[3] For example, an enzyme that catalyzed this reaction would be an oxidoreductase: In this example, A is the reductant (electron donor) and B is the oxidant (electron acceptor).
Proper names of oxidoreductases are formed as "donor:acceptor oxidoreductase"; however, other names are much more common.