Ectonucleoside Triphosphate Diphosphohydrolase 1 (ENTPD1)

Endothelial cells have the ability to regulate platelet activation, in part by the surface expression of ATP diphosphohydrolase (ATPDase; EC 3.6.1.5). ATPDase hydrolyzes extracellular ATP and ADP to AMP, which is further converted to adenosine by another enzyme, 5-prime nucleotidase. ADP is a powerful agonist for platelet recruitment and adhesion; adenosine is an antagonist of these processes. 

CD39 was found to have both immunologic identity to, and functional characteristics of, vascular ATPDase. By Northern blot analysis, Chadwick and Frischauf (1998) found that CD39 is expressed as a major 3.2- and a minor 3.6-kb mRNA in several tissues. Additional bands were observed in a few tissues.