Semicarbazide-Sensitive Amine Oxidase

Semicarbazide-Sensitive Amine Oxidase, also known as SSAO and AOC3 (Amine oxidase, copper containing 3), is an enzyme in humans that catalyzes the oxidative conversion of amines to aldehydes in the presence of copper and quinone as cofactors. It has adhesive properties and also has functional monoamine oxidase activity.

Like monoamine oxidase (MAO-A and MAO-B), SSAO can deaminate short-chain primary amines, but is insensitive to MAO inhibitors. Semicarbazide was one of the first compounds found to inhibit this enzyme.

Several psychoactive compounds are substrates of SSAO (mescaline, tyramine, phenethylamine, etc.). Often these compounds are also substrates of MAO-A and MAO-B enzymes (phenethylamine for example).

In humans, cell-associated SSAO is mainly expressed in smooth muscle cells of the vasculature (blood vessels), endothelial cells of lymphatic organs, liver sinusoidal tissue, brain microvasculature (small blood vessels in the brain), and adipocytes (fat cells).[5]


Substrates


Inhibitors

Potent Inhibitors Inhibitors Strength Dosage Verified in Man
Cranesbill (contains geraniin) ? ? ?
Geraniin IC50=0.00658 mM ? ?
Heptylamine IC50=0.007 mM ? ?
Hexylamine IC50=0.06 mM ? ?
Nonylamine IC50=0.000002 mM ? ?
Octylamine IC50=0.002 mM ? ?
Phenylhydrazine IC50=0.00003 mM ? ?
Weak Inhibitors           Strength Dosage Verified in Man
Butylamine IC50=0.1 mM ? ?
Caffeine IC50=0.8 ± 0.3 mM[1] [4] ? ?
Coffee (contains caffeine) ? ? ?
Methylamine IC50=1 mM ? ?
Penthylamine IC50=0.1 mM ? ?
Phenethylamine IC50=0.3 mM ? ?
Tryptamine IC50=0.3 mM ? ?
Inhibitors (Unknown Potency) Strength Dosage Verified in Man
Aminoguanidine [2] ? ? ?
B-24 [2] ? ? ?
Benserazide [2] ? ? ?
Carbidopa [2] ? ? ?
FLA 336 [2] ? ? ?
Galactosamine [3] ? ? ?
Glucosamine [3] ? ? ?
Hydralazine [2] ? ? ?
Hydroxylamine [2] ? ? ?
Iproniazid [2] ? ? ?
MDL-72145 [2] ? ? ?
MDL-72974A [2] ? ? ?
Mannosamine [3] ? ? ?
(+)Mexiletine [2] ? ? ?
Phenelzine [2] ? ? ?
Phyllanthus urinaria L (contains geraniin) ? ? ?
Procarbazine [2] ? ? ?
Propargylamine [2] ? ? ?
Pyridoxamine [2] ? ? ?
Semicarbazide [2] ? ? ?
1-(isoquinolin-1-ylcarbonyl)pyrrolidine-2-carboxamide [6] ? ? ?

Bibliography
1. A. Olivieri and K. Tipton;
Inhibition of Bovine Plasma Semicarbazide-Sensitive Amine Oxidase by Caffeine School of Biochemistry and Immunology, Trinity College, Dublin 2, Ireland; Received 18 January 2010; revised 7 March 2010; accepted 16 March 2010; J Biochem Molecular Toxicology DOI 10:1002/jbt; Download Attached PDF
2. K. Magyar, Z. Mészáros, and P. Mátyus
Semicarbazide-sensitive amine oxidase. Its physiological significance; Department of Pharmacodynamics and Department of Organic Chemistry, Faculty of Pharmacy, Semmelweis University, Budapest, Hungary; © 2001 IUPAC, Pure and Applied Chemistry 73, 1393–1400 Download Attached PDF
3. O'Sullivan J, Davey G, O'Sullivan M, Tipton KF;
Hydrogen peroxide derived from amine oxidation mediates the interaction between aminosugars and semicarbazide-sensitive amine oxidase; School of Biochemistry and Immunology, Trinity College, Dublin, Ireland; J Neural Transm. 2007;114(6):751-6. Epub 2007 Mar 31; PubMed PMID: 17401531
4. Che B, Wang L, Zhang Z, Zhang Y, Deng Y;
Distribution and accumulation of caffeine in rat tissues and its inhibition on Semicarbazide-sensitive amine oxidase; School of Life Science, Beijing Institute of Technology, Beijing 100081, China; Neurotoxicology. 2012 Oct;33(5):1248-53. doi: 10.1016/j.neuro.2012.07.004. Epub 2012 Jul 25; PubChem PMID: 22841599
5. Luisa M. Salter-Cid, Eric Wang, Anne M. O'Rourke, Andrew Miller, Hongfeng Gao, Li Huang, Arnie Garcia and Matthew D. Linnik;
Anti-Inflammatory Effects of Inhibiting the Amine Oxidase Activity of Semicarbazide-Sensitive Amine Oxidase; La Jolla Pharmaceutical Company, San Diego, California; Received May 20, 2005; accepted August 02, 2005; PubMed PMID: 16081681 (Download Attached PDF Document)
6. Dunkel P, Gelain A, Barlocco D, Haider N, Gyires K, Sperlágh B, Magyar K, Maccioni E, Fadda A, Mátyus P;
Semicarbazide-sensitive amine oxidase/vascular adhesion protein 1: recent developments concerning substrates and inhibitors of a promising therapeutic target. Curr Med Chem. 2008;15(18):1827-39; Department of Organic Chemistry, Semmelweis University, Hogyes Endre utca 7, H-1092 Budapest, Hungary; PubMed PMID: 18691041

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