The presence of diadenosine 5',5'''-P1,P3-triphosphate (Ap3A) in human platelets

Diadenosine triphosphate (Ap3A) has been identified and quantified in human platelets using a coupled enzymatic assay specific for Ap3A, after fractionation of acidic extracts with high-performance liquid chromatography. Upon thrombin-induced aggregation, Ap3A is released together with the homologue diadenosine tetraphosphate (Ap4A). Extracts of human platelets do also contain enzymatic activities that degrade diadenosine tetraphosphate as well as diadenosine triphosphate. These enzymes, however, are not released during thrombin-induced aggregation of the platelets.