Diamine oxidase, also known as histaminase, is an enzyme (EC126.96.36.199) involved in the metabolism, oxidation, and inactivation of histamine in animals. Highest content is observed in the digestive tract and placenta. It is also secreted by eosinophils. In case of a shortage of diamine oxidase in the human body, it may appear as an allergy or histamine intolerance.
Diamine oxidase should not be confused with D-amino acid oxidase as they are both sometimes referred to as DAO.