Vascular Adhesion Protein 1 (VAP-1), also called AOC3 (amine oxidase copper-containing 3) or SSAO (semicarbazide-sensitive amine oxidase) is a type II transmembrane sialoglycoprotein that is upregulated on endothelial cells by inflammation. The 170kD disulfide-linked homodimer of 763 aa units is an ectoenzyme that deaminates amines, forming aldehydes and hydrogen peroxide. It also mediates lymphocyte rolling, adhesion and possibly extravasation during inflammation. Adipocytes can release a soluble form via metalloproteinase cleavage. Human and mouse VAP-1 share 83% aa identity.