Semicarbazide-sensitive amine oxidase

Amine oxidase, copper containing 3 (vascular adhesion protein 1)
PDB rendering based on 1pu4.
Available structures
PDB Ortholog search: RCSB
RNA expression pattern

Amine oxidase, copper containing 3 (vascular adhesion protein 1), also known as semicarbazide-sensitive amine oxidase (SSAO, copper-containing amine:oxygen oxidoreductase), is an enzyme that in humans is encoded by the AOC3 gene.[1][2][3]


Copper amine oxidases catalyze the oxidative conversion of amines to aldehydes in the presence of copper and quinone cofactor. The product is a major protein on the adipocyte plasma membrane. It has adhesive properties and also has functional monoamine oxidase activity.[3]

Like monoamine oxidase (MAO), SSAO can deaminate short-chain primary amines, but is insensitive to MAO inhibitors. Semicarbazide inhibits the enzyme, in addition to other hydrazines, hydroxylamine and propargylamine. However, hydrazines are weak inhibitors and stronger inhibitors have been developed.

SSAO is found in the smooth muscle of blood vessels and various other tissues. The physiological function of SSAO is not well understood. Development of blood vessels, lipolysis regulation, and detoxication are suggested. It may function as a scavenger enzyme to assist MAO. However, the oxidation process generates harmful products that may be involved in causing atherosclerosis and vascular damage in diabetes. Elevation of SSAO activity is observed in atherosclerosis, diabetes mellitus, obesity, carotid plaque cases and varicosities.

There are SSAO inhibitors in development.[4][5]

Clinical relevance

Semicarbazide-cadmium therapy has been used to alleviate the symptoms of cancers, but the APIs have significant toxicity.


Further reading