Ecto-adenosine deaminase: An ecto-enzyme and a costimulatory protein acting on a variety of cell surface receptors
✍ Scribed by Rafael Franco; Josefa Mallol; Vicent Casadó; Carmen Lluis; Enric I. Canela; Carles Saura; Julià Blanco; Francisco Ciruela
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 139 KB
- Volume
- 45
- Category
- Article
- ISSN
- 0272-4391
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✦ Synopsis
Adenosine deaminase (ADA, E.C. 3.5.4.4) is an enzyme of the purine metabolism that converts adenosine (Ado) and 2′deoxyadenosine (dAdo) into inosine and 2′deoxyinosine, respectively. The enzyme has been the object of considerable interest because the congenital defect causes severe combined immunodeficiency (SCID). In the past 12 years, ADA, which was considered to be cytosolic, has been found on the surface of many cells; therefore, it has to be also considered as an ecto-enzyme (ecto-ADA). There is recent evidence about a specific role for ecto-ADA that is different from that of intracellular ADA. Apart from degrading extracellular Ado or dAdo, which are toxic for lymphocytes and other cells, ecto-ADA has got an extraenzymatic function by means of its interaction with cell surface proteins. The interactions in which ecto-ADA participates are summarized, and an overview of the known and suspected extraenzymatic roles for ecto-ADA is presented.