Could be involved in the spore pigmentation and melanin production. Catalyzes the oxidative coupling of 2-aminophenols to form the 2-aminophenoxazinone chromophore. 2-aminophenoxazinone synthesis proceeds via a sequence of three consecutive 2-electron aminophenol oxidations. First, the o-aminophenol is oxidized by two electrons to the quinone imine, which then conjugates to a second o-aminophenol molecule while still bound to the enzyme. This product is further oxidized by two electrons to give rise to the p-quinone imine. The last two steps of the reaction, another conjugation to generate the tricyclic structure and a final two-electron oxidation to yield the 2-aminophenoxazinone product, are thought to be non-enzymatic. It can also uuse 3-hydroxyanthranilic acid (HAA), 4-methyl-3-hydroxyanthranilic acid (MHA), 3,4-dihydroxy-L-phenylalanine (L-DOPA), ferrocyanide and thiophenol as substrates. 4 2-aminophenol + 3 O2 = 2 2-aminophenoxazin-3-one + 6 H2O Binds 5 copper ions per monomer. Optimum pH is 5. Homodimer (small form) or homohexamer (large form). Belongs to the multicopper oxidase family. Truncated N-terminus.