This is a copper-containing oxidase that functions in the formation of pigments such as melanins and other polyphenolic compounds. Catalyzes the rate-limiting conversions of tyrosine to DOPA, DOPA to DOPA-quinone and possibly 5,6 dihydroxyindole to indole-5'6 quinone (By similarity). 2 L-dopa + O2 = 2 H2O + 2 L-dopaquinone L-tyrosine + O2 = H2O + L-dopaquinone Binds 2 copper ions per subunit. Upon activation, a trypsin type protease cleaves prophenol oxidase to yield the active enzyme. Belongs to the tyrosinase family.