Catalyzes the oxidative deamination of primary and some secondary amine such as neurotransmitters, with concomitant reduction of oxygen to hydrogen peroxide and has important functions in the metabolism of neuroactive and vasoactive amines in the central nervous system and peripheral tissues (PubMed:18391214, PubMed:9162023). Preferentially oxidizes serotonin (PubMed:20493079). Also catalyzes the oxidative deamination of kynuramine to 3-(2-aminophenyl)-3-oxopropanal that can spontaneously condense to 4-hydroxyquinoline (PubMed:18391214). a secondary aliphatic amine + H2O + O2 = a primary amine + an aldehyde + H2O2 an aliphatic amine + H2O + O2 = an aldehyde + H2O2 + NH4(+) (R)-adrenaline + H2O + O2 = (R)-3,4-dihydroxymandelaldehyde + H2O2 + methylamine dopamine + H2O + O2 = 3,4-dihydroxyphenylacetaldehyde + H2O2 + NH4(+) H2O + O2 + tyramine = (4-hydroxyphenyl)acetaldehyde + H2O2 + NH4(+) (R)-noradrenaline + H2O + O2 = (R)-3,4-dihydroxymandelaldehyde + H2O2 + NH4(+) H2O + O2 + serotonin = (5-hydroxyindol-3-yl)acetaldehyde + H2O2 + NH4(+) H2O + kynuramine + O2 = 3-(2-aminophenyl)-3-oxopropanal + H2O2 + NH4(+) H2O + O2 + tryptamine = H2O2 + indole-3-acetaldehyde + NH4(+) 2-phenylethylamine + H2O + O2 = 2-phenylacetaldehyde + H2O2 + NH4(+) Monomer, homo- or heterodimer (containing two subunits of similar size). Each subunit contains a covalently bound flavin. Enzymatically active as monomer (By similarity). Belongs to the flavin monoamine oxidase family. Approaching happiness - Issue 172 of August 2015