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Amine oxidase, copper containing 3
Protein AOC3 PDB 1pu4.png
PDB rendering based on 1pu4.
Available structures
PDB Ortholog search: PDBe, RCSB
Symbols AOC3 ; HPAO; SSAO; VAP-1; VAP1
External IDs OMIM603735 MGI1306797 HomoloGene2770 ChEMBL: 3437 GeneCards: AOC3 Gene
EC number
RNA expression pattern
PBB GE AOC3 204894 s at tn.png
More reference expression data
Species Human Mouse
Entrez 8639 11754
Ensembl ENSG00000131471 ENSMUSG00000019326
UniProt Q16853 O70423
RefSeq (mRNA) NM_001277731 NM_009675
RefSeq (protein) NP_001264660 NP_033805
Location (UCSC) Chr 17:
41 – 41.01 Mb
Chr 11:
101.33 – 101.34 Mb
PubMed search [1] [2]

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[edit]

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


  1. ^ Zhang X, McIntire WS (November 1996). "Cloning and sequencing of a copper-containing, topa quinone-containing monoamine oxidase from human placenta". Gene 179 (2): 279–86. doi:10.1016/S0378-1119(96)00387-3. PMID 8972912. 
  2. ^ Smith DJ, Salmi M, Bono P, Hellman J, Leu T, Jalkanen S (July 1998). "Cloning of Vascular Adhesion Protein 1 Reveals a Novel Multifunctional Adhesion Molecule". J. Exp. Med. 188 (1): 17–27. doi:10.1084/jem.188.1.17. PMC 2525535. PMID 9653080. 
  3. ^ a b "Entrez Gene: AOC3 amine oxidase, copper containing 3 (vascular adhesion protein 1)". 
  4. ^ O'Rourke AM, Wang EY, Miller A, et al. (2008). "Anti-inflammatory effects of LJP 1586 [Z-3-fluoro-2-(4-methoxybenzyl)allylamine hydrochloride], an amine-based inhibitor of semicarbazide-sensitive amine oxidase activity". The Journal of Pharmacology and Experimental Therapeutics 324 (2): 867–75. doi:10.1124/jpet.107.131672. PMID 17993604. 
  5. ^ Wang EY, Gao H, Salter-Cid L, et al. (2006). "Design, synthesis, and biological evaluation of semicarbazide-sensitive amine oxidase (SSAO) inhibitors with anti-inflammatory activity". Journal of Medical Chemistry 49 (7): 2166–73. doi:10.1021/jm050538l. PMID 16570912. 

Further reading[edit]