Plays a role in melanin biosynthesis. Catalyzes the oxidation of 5,6-dihydroxyindole-2-carboxylic acid (DHICA) into indole-5,6-quinone-2-carboxylic acid. May regulate or influence the type of melanin synthesized. Also to a lower extent, capable of hydroxylating tyrosine and producing melanin. Contains bound zinc ions after heterologous expression in insect cells. Pigment biosynthesis; melanin biosynthesis. Monomer (By similarity). Interacts with ATP7A (By similarity). Located to mature stage III and IV melanosomes and apposed endosomal tubular membranes. Transported to pigmented melanosomes by the BLOC-1 complex. Proper trafficking to melanosome is regulated by SGSM2, ANKRD27, RAB9A, RAB32 and RAB38. Glycosylated. Belongs to the tyrosinase family. The precise function of this protein in melanin biosynthesis is still under debate. DHICA oxidase activity is controversial. The mouse protein has been shown to have DHICA oxidase activity (By similarity). In contrast, the human protein was shown lack DHICA oxidase activity, or to have DHICA oxidase activity only in the presence of Cu(2+), but not with Zn(2+) (By similarity).