Tyrosinase (Agaricus bisporus) (PPO)

Mushroom tyrosinase, primarily isolated from the common button mushroom Agaricus bisporus, is a copper-containing enzyme that serves as a rate-limiting catalyst in the production of melanin (UniProt: P00431). It possesses two distinct catalytic activities: monophenolase activity, which hydroxylates L-tyrosine to L-DOPA, and diphenolase activity, which oxidizes L-DOPA to dopaquinone (PubMed: 25553383). Although it is a fungal enzyme, it is the most widely used biochemical model for studying human tyrosinase due to its high homology, commercial availability, and ease of purification. In the pharmaceutical and cosmetic industries, it is the primary target for developing skin-lightening agents and treatments for hyperpigmentation disorders such as melasma and solar lentigines (PubChem: Tyrosinase). Inhibitors of this enzyme, such as kojic acid and hydroquinone, are used to reduce melanin synthesis, though they must be monitored for safety concerns like skin irritation and potential cytotoxicity. Beyond medicine, mushroom tyrosinase is also a focus of the food industry, where its inhibition is sought to prevent the enzymatic browning of produce.

Other names

Mushroom tyrosinasePolyphenol oxidaseMonophenol monooxygenaseCatechol oxidaseMonophenol, L-dopa:oxygen oxidoreductase

Inhibition of the catalytic activity of tyrosinase, specifically blocking the hydroxylation of L-tyrosine (monophenolase activity) and the oxidation of L-DOPA to dopaquinone (diphenolase activity) to prevent melanin formation (PubMed: 29035199).