Flavoenzyme involved in polyamine back-conversion (By similarity). Catalyzes the oxidation of the secondary amino group of polyamines, such as spermine and spermidine (By similarity). Binds 1 FAD per subunit. Amine and polyamine degradation; spermine degradation. Induced by salt stress in shoots and roots (PubMed:20472577). Induced by treatment with jasmonate (PubMed:28786735). Belongs to the flavin monoamine oxidase family. Truncated N-terminus. Truncated N-terminus.