Diamine oxidase

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Diamine oxidase
Diamine oxidase dimer, Human
EC no.
IntEnzIntEnz view
ExPASyNiceZyme view
MetaCycmetabolic pathway
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO
Available structures
PDBOrtholog search: PDBe RCSB
AliasesAOC1, ABP, ABP1, DAO, DAO1, KAO, amine oxidase, copper containing 1, amine oxidase copper containing 1
External IDsOMIM: 104610 MGI: 1923757 HomoloGene: 68159 GeneCards: AOC1
RefSeq (mRNA)



RefSeq (protein)



Location (UCSC)Chr 7: 150.82 – 150.86 MbChr 6: 48.85 – 48.89 Mb
PubMed search[3][4]
View/Edit HumanView/Edit Mouse

Diamine oxidase (DAO), also known "amine oxidase, copper-containing, 1" (AOC1), formerly called histaminase,[5] is an enzyme (EC involved in the metabolism, oxidation, and inactivation of histamine and other polyamines such as putrescine or spermidine in animals. It belongs to the amine oxidase (copper-containing) (AOC) family of amine oxidase enzymes. In humans, DAO it is encoded by AOC1 gene.

The highest levels of DAO expression are observed in the digestive tract and the placenta. In humans, a certain subtype of cells of the placenta, namely the extravillous trophoblasts, express the enzyme and secrete it into the blood stream of a pregnant woman. Lowered diamine oxidase values in maternal blood in early pregnancy might be an indication for trophoblast-related pregnancy disorders like early-onset preeclampsia.[6] Normally the enzyme is not or only very scarcely present in the blood circulation of humans, but it increases vastly in pregnant women suggesting a protective mechanism against adverse histamine.[6] It is also secreted by eosinophils.[7][8] In case of a shortage of diamine oxidase in the human body, it may appear as an allergy or histamine intolerance.[9][10]


For people with a histamine intolerance, the benefits of supplementation are inconclusive due to limited research. [11]


  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000002726 - Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000029811 - Ensembl, May 2017
  3. ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. ^ Wolvekamp MC, de Bruin RW (1994). "Diamine oxidase: an overview of historical, biochemical and functional aspects". Digestive Diseases. 12 (1): 2–14. doi:10.1159/000171432. PMID 8200121.
  6. ^ a b Velicky P, Windsperger K, Petroczi K, Pils S, Reiter B, Weiss T, et al. (April 2018). "Pregnancy-associated diamine oxidase originates from extravillous trophoblasts and is decreased in early-onset preeclampsia". Scientific Reports. 8 (1): 6342. Bibcode:2018NatSR...8.6342V. doi:10.1038/s41598-018-24652-0. PMC 5910386. PMID 29679053.
  7. ^ Zeiger RS, Colten HR (February 1977). "Histaminase release from human eosinophils". Journal of Immunology. 118 (2): 540–3. PMID 402420.
  8. ^ Agúndez JA, Ayuso P, Cornejo-García JA, Blanca M, Torres MJ, Doña I, et al. (2012). "The diamine oxidase gene is associated with hypersensitivity response to non-steroidal anti-inflammatory drugs". PLOS ONE. 7 (11): e47571. Bibcode:2012PLoSO...747571A. doi:10.1371/journal.pone.0047571. PMC 3495953. PMID 23152756.
  9. ^ Manzotti G, Breda D, Di Gioacchino M, Burastero SE (March 2016). "Serum diamine oxidase activity in patients with histamine intolerance". International Journal of Immunopathology and Pharmacology. 29 (1): 105–11. doi:10.1177/0394632015617170. PMC 5806734. PMID 26574488.
  10. ^ Music E, Silar M, Korosec P, Kosnik M, Rijavec M (2011). "Serum diamine oxidase (DAO) activity as a diagnostic test for histamine intolerance". Clinical and Translational Allergy. 1 (Suppl 1): P115. doi:10.1186/2045-7022-1-S1-P115. PMC 3354134.
  11. ^ "Diamine Oxidase (DAO): Benefits, Dosage, and Safety". Healthline. 2019-03-04. Retrieved 2022-07-31.

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