Involved in the biosynthesis of pyridine alkaloid natural products, leading mainly to the production of anabasine, anatabine, nicotine and nornicotine, effective deterrents against herbivores with antiparasitic and pesticide properties (neurotoxins); nornicotine serves as the precursor in the synthesis of the carcinogen compound N'-nitrosonornicotine (NNN) (PubMed:17174363, PubMed:17283012, PubMed:16656744). Amine oxidase which mediates the deamination of N-methylputrescine to produce 4-methylaminobutanal (PubMed:17174363, PubMed:17283012). Oxidizes preferentially N-methylated amines (PubMed:24287136). an aliphatic amine + H2O + O2 = an aldehyde + H2O2 + NH4(+) H2O + N-methylputrescine + O2 = 4-methylaminobutanal + H2O2 + NH4(+) Binds 1 copper ion per subunit (By similarity). Can also use zinc ion as cofactor (By similarity). Contains 1 topaquinone per subunit. Alkaloid biosynthesis; nicotine biosynthesis. Homodimer. Mainly expressed in roots, and, to a lower extent, in stems. Accumulates in roots upon auxin deprivation (PubMed:17174363). Induced by jasmonic acid (MeJA) (PubMed:17174363, PubMed:17283012, PubMed:24287136). Topaquinone (TPQ) is generated by copper-dependent autoxidation of a specific tyrosyl residue. Altered nicotine biosynthesis. Belongs to the copper/topaquinone oxidase family.