Catalyzes the oxidative deamination of primary amines to the corresponding aldehydes with the concomitant production of hydrogen peroxide and ammonia (PubMed:19588076, PubMed:24304424, PubMed:9653080). Has a preference for the primary monoamines methylamine and benzylamine (PubMed:19588076, PubMed:9653080). Could also act on 2-phenylethylamine but much less efficiently (PubMed:19588076). At endothelial cells surface can also function as a cell adhesion protein that participates in lymphocyte extravasation and recirculation by mediating the binding of lymphocytes to peripheral lymph node vascular endothelial cells in an L-selectin-independent fashion (PubMed:9254657, PubMed:9653080). ; [Isoform 2]: Has no semicarbazide-sensitive amine oxidase (SSAO) activity.
