IUBMB Enzyme Nomenclature


Accepted name: diamine oxidase

Reaction: histamine + H2O + O2 = (imidazol-4-yl)acetaldehyde + NH3 + H2O2

Other name(s): amine oxidase (ambiguous); amine oxidase (copper-containing) (ambiguous); CAO (ambiguous); Cu-containing amine oxidase (ambiguous); copper amine oxidase (ambiguous); diamine oxidase (ambiguous); diamino oxhydrase (ambiguous); histaminase; histamine deaminase (incorrect); semicarbazide-sensitive amine oxidase (incorrect); SSAO (incorrect)

Systematic name: histamine:oxygen oxidoreductase (deaminating)

Comments: A group of enzymes that oxidize diamines, such as histamine, and also some primary monoamines but have little or no activity towards secondary and tertiary amines. They are copper quinoproteins (2,4,5-trihydroxyphenylalanine quinone) and, like EC (primary-amine oxidase) but unlike EC (monoamine oxidase), they are sensitive to inhibition by carbonyl-group reagents, such as semicarbazide.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number:


1. Zeller, E.A. Diamine oxidases. In: Boyer, P.D., Lardy, H. and Myrbäck, K. (Eds), The Enzymes, 2nd edn, vol. 8, Academic Press, New York, 1963, pp. 313-335.

2. Crabbe, M.J., Waight, R.D., Bardsley, W.G., Barker, R.W., Kelly, I.D. and Knowles, P.F. Human placental diamine oxidase. Improved purification and characterization of a copper- and manganese-containing amine oxidase with novel substrate specificity. Biochem. J. 155 (1976) 679-687. [PMID: 182134]

3. Chassande, O., Renard, S., Barbry, P. and Lazdunski, M. The human gene for diamine oxidase, an amiloride binding protein. Molecular cloning, sequencing, and characterization of the promoter. J. Biol. Chem. 269 (1994) 14484-14489. [PMID: 8182053]

4. Houen, G. Mammalian Cu-containing amine oxidases (CAOs): new methods of analysis, structural relationships, and possible functions. APMIS Suppl. 96 (1999) 1-46. [PMID: 10668504]

5. Elmore, B.O., Bollinger, J.A. and Dooley, D.M. Human kidney diamine oxidase: heterologous expression, purification, and characterization. J. Biol. Inorg. Chem. 7 (2002) 565-579. [PMID: 12072962]

[EC created 2007 (EC created 1961, part-incorporated 2008)]

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