For example, an enzyme that catalyzed this reaction would be an oxidoreductase:
:A + B → A + B
In this example, A is the reductant (electron donor) and B is the oxidant (electron acceptor).
In biochemical reactions, the redox reactions are sometimes more difficult to see, such as this reaction from glycolysis:
:P + glyceraldehyde-3-phosphate + NAD → NADH + H + 1,3-bisphosphoglycerate
In this reaction, NAD is the oxidant (electron acceptor), and glyceraldehyde-3-phosphate is the reductant (electron donor).