Has a monoamine oxidase activity with substrate specificity for 2-phenylethylamine and tryptamine. May play a role in adipogenesis. May be a critical modulator of signal transmission in retina (By similarity). an aliphatic amine + H2O + O2 = an aldehyde + H2O2 + NH4(+) Binds 1 copper ion per subunit. Binds 2 calcium ions per subunit. Contains 1 topaquinone per subunit. Homodimer; disulfide-linked (By similarity). Forms a heterodimer with AOC3 (By similarity). Significantly much highly expressed in retina. Topaquinone (TPQ) is generated by copper-dependent autoxidation of a specific tyrosyl residue. Belongs to the copper/topaquinone oxidase family.