This is a copper-containing oxidase that functions in the formation of pigments such as melanins and other polyphenolic compounds (By similarity). Catalyzes the initial and rate limiting step in the cascade of reactions leading to melanin production from tyrosine. In addition to hydroxylating tyrosine to DOPA (3,4-dihydroxyphenylalanine), also catalyzes the oxidation of DOPA to DOPA-quinone (PubMed:19101648, PubMed:18950728, PubMed:6798971). 2 L-dopa + O2 = 2 H2O + 2 L-dopaquinone L-tyrosine + O2 = H2O + L-dopaquinone Binds 2 copper ions per subunit. Activated by trypsin, chymotrypsin and subtilisin (PubMed:6798971, PubMed:6814426). Activated by alpha-chymotrypsin, thermolysin and Pronase. Inhibited by its product L-DOPA and tyrosine (PubMed:6814426). Active tyrosinase has been found as a homodimer and homotetramer. Frog skin. By seasons. Highest levels in the winter time and lowest during the summer (at protein level). Belongs to the tyrosinase family.