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. Expressed in lung, spleen, heart and kidney. Topaquinone (TPQ) is generated by copper-dependent autoxidation of a specific tyrosyl residue. Inhibited by amiloride in a competitive manner. Belongs to the copper/topaquinone oxidase family.