Bis(5'-adenosyl)-triphosphatase ENPP4 (ENPP4)

Hydrolyzes extracellular Ap3A into AMP and ADP, and Ap4A into AMP and ATP.

Ap3A and Ap4A are diadenosine polyphosphates believed to induce proliferation of vascular smooth muscle cells.

Acts as a procoagulant, mediating platelet aggregation at the site of nascent thrombus via release of ADP from Ap3A and activation of ADP receptors. .