Oxidizes preferentially the aliphatic diamine putrescine with production of the corresponding aldehyde, ammonia and hydrogen peroxide. May be involved in the regulation of developmental programmed cell death (PCD) in both vascular tissue and the root cap (PubMed:9681017). Required for jasmonic acid-(MeJA) mediated early protoxylem differentiation associated with putrescine levels reduction and H(2)O(2) accumulation in roots (PubMed:25883242). an aliphatic amine + H2O + O2 = an aldehyde + H2O2 + NH4(+) Contains 1 topaquinone per subunit. Binds 1 copper ion per subunit (By similarity). Can also use zinc ion as cofactor (By similarity). Binds 1 Mn(2+) ion per subunit. Repressed by semi-carbazide, a specific and irreversible inhibitor of copper amine oxidases. Homodimer. Expressed in the vascular tissues at the division/differentiation transition zone. Levels peak 3-4 days after germination. Expressed following temporally and spatially discrete patterns of gene expression in lateral root cap cells, vascular tissue of roots, developing leaves, the hypocotyl, and in the style/stigmatal tissue (PubMed:9681017). Expressed at the early stages of vascular tissue differentiation in roots; strong accumulation in the protoxylem at the transition, elongation, and maturation zones (PubMed:25883242). Accumulates in developing tracheary elements before lignification. Present in cells destined to undergo programmed cell death (PCD) in both vascular tissue and the root cap. In flowers, restricted spatial and temporal distribution; at stage 11-13, after papillae formation, accumulates in tracheary elements of style and stigmate (PubMed:9681017). Induced by jasmonic acid (MeJA) in vascular tissues, especially at the transition and elongation zones. Topaquinone (TPQ) is generated by copper-dependent autoxidation of a specific tyrosyl residue. Impaired sensitivity to jasmonic acid (MeJA). Belongs to the copper/topaquinone oxidase family. Extended N-terminus.