Oxidase

An oxidase is any enzyme that catalyzes an oxidation/reduction reaction involving molecular oxygen (O2) as the electron acceptor. In these reactions, oxygen is reduced to water (H2O) or hydrogen peroxide (H2O2).

The oxidase are a subclass of the oxidoreductases.

Examples
An important example is cytochrome c oxidase, the key enzyme that allows the body to employ oxygen in the generation of energy and the final component of the electron transfer chain. Other examples are:
 * glucose oxidase
 * monoamine oxidase
 * cytochrome P450 oxidase
 * NADPH oxidase
 * Xanthine oxidase
 * L-gulonolactone oxidase
 * laccase
 * lysyl oxidase

Oxidase test
In microbiology, the oxidase test is used as a phenotypic character for the identification of bacterial strains; it determines whether a given bacterium produces cytochrome oxidases (and therefore utilizes oxygen with an electron transfer chain).

Bacteria that can or must utilize oxygen are called (facultative) aerobic bacteria.