Tyrosinase

Tyrosinase (monophenol monooxygenase) (CAS number: 9002-10-2) is an enzyme that catalyses the oxidation of phenols (such as tyrosine) and is widespread in plants and animals. Tyrosinase is a copper-containing enzyme present in plant and animal tissues that catalyzes the production of melanin and other pigments from tyrosine by oxidation, as in the blackening of a peeled or sliced potato exposed to air. When a person has a mutated tyrosinase gene they have albinism, a hereditary disease that one in every 17,000 person has in the United States.

Chemical Reactions
Tyrosinase carries out the oxidation of phenols such as tyrosine and catechol using dioxygen (O2). In the presence of catechol, benzoquinone is formed (see reaction below). Hydrogens removed from catechol combine with oxygen to form water.



The active site in the tyrosinase enzyme contains two closely located copper atoms that interact with dioxygen to form a highly reactive chemical intermediate that then oxidizes the substrate. The activity of tyrosinase is similar to catechol oxidase, a related class of copper oxidases.