AOC3
Description
The AOC3 (amine oxidase copper containing 3) is a protein-coding gene located on chromosome 17.
AOC3 (Amine oxidase, copper containing 3), also known as vascular adhesion protein (VAP-1) and HPAO, is an enzyme encoded by the AOC3 gene located on human chromosome 17. This protein belongs to the semicarbazide-sensitive amine oxidase (SSAO) family of enzymes and is linked to several vascular diseases. VAP-1 is a type 1 membrane-bound glycoprotein with a distal adhesion domain and an enzymatically active amine oxidase site outside the membrane. The AOC3 gene maps to 17q21 and contains 6 exons. Amine oxidases are a family of enzymes that catalyze the oxidation of various endogenous amines, including histamine or dopamine. VAP-1 represents the copper-dependent class of amine oxidases, alongside lysyl oxidase and lysine demethylase, and is one of four known in humans. The other class is flavin-dependent, such as monoamine oxidase (MAO) A and B. VAP-1 specifically catalyzes the oxidative conversion of primary amines (methylamine and aminoacetone) to aldehydes (formaldehyde and methylglyoxal), ammonium, and hydrogen peroxide in the presence of copper and quinone cofactor. Primarily localized on the cell surface of the adipocyte plasma membrane, circulating VAP-1 has been identified as the primary source of SSAO in human serum. Serum VAP-1 originates from various tissues.
AOC3 catalyzes the oxidative deamination of primary amines to their corresponding aldehydes, simultaneously producing hydrogen peroxide and ammonia. It exhibits a preference for primary monoamines like methylamine and benzylamine. While it can also act on 2-phenylethylamine, its efficiency is significantly lower. At the surface of endothelial cells, AOC3 functions as a cell adhesion protein, facilitating lymphocyte extravasation and recirculation by mediating the binding of lymphocytes to peripheral lymph node vascular endothelial cells in an L-selectin-independent manner.
AOC3 is also known as HPAO, SSAO, VAP-1, VAP1.
