Vascular adhesion protein‑1 (VAP-1)

Vascular adhesion protein‑1 (VAP-1) is a transmembrane glycoprotein primarily expressed in vascular endothelium and pericytes. It belongs to the copper-containing amine oxidase family and uniquely combines enzymatic amine oxidase activity—catalyzing the oxidative deamination of primary amines—with adhesive properties that facilitate leukocyte rolling, adhesion, and extravasation in inflamed tissues. The AOC3 gene encodes VAP-1. Its enzymatic action produces hydrogen peroxide, ammonium, and aldehydes, important for leukocyte-endothelial interactions and signal transduction. VAP-1’s dual activity plays a critical role in immune response, vascular biology, and metabolic regulation, making it a target for drug development in inflammatory, cardiovascular, and metabolic diseases. Circulating sVAP-1 serves as a biomarker in several pathologies. Therapeutic modulation is under investigation, with inhibitors in preclinical and clinical studies.

Other names

Amine oxidase copper-containing 3 (AOC3)Semicarbazide-sensitive amine oxidase (SSAO)Primary amine oxidase (EC 1.4.3.21)

VAP-1 inhibitors block enzymatic oxidative deamination of primary amines, which in turn reduces generation of hydrogen peroxide and other mediators, impairs leukocyte adhesion, and blunts tissue inflammation