Copper-containing oxidase that catalyzes both the o-hydroxylation of monophenols and the subsequent oxidation of the resulting o-diphenols into reactive o-quinones, which evolve spontaneously to produce intermediates, which associate in dark brown pigments. Involved in the initial step of melanin synthesis. Melanins constitute a mechanism of defense and resistance to stress such as UV radiations, free radicals, gamma rays, dehydratation and extreme temperatures, and contribute to the fungal cell-wall resistance against hydrolytic enzymes in avoiding cellular lysis. Fungal pigments are also involved in the formation and stability of spores (By similarity). 2 L-dopa + O2 = 2 H2O + 2 L-dopaquinone L-tyrosine + O2 = H2O + L-dopaquinone Binds 2 copper ions per subunit. Heterotetramer. Expressed during the fruiting body stage. The C-ter is probably cleaved after Gly-378 since the mature active protein is smaller than the protein encoded by the gene. Belongs to the tyrosinase family.