This is a copper-containing oxidase that functions in the formation of pigments such as melanins and other polyphenolic compounds. 2 L-dopa + O2 = 2 H2O + 2 L-dopaquinone L-tyrosine + O2 = H2O + L-dopaquinone Binds 2 copper ions per subunit. Activated by acidifying treatment at pH 3.0. Homotetramer. The N-terminus is blocked. Belongs to the tyrosinase family.