A diadenosine polyphosphate stored in secretory granules of chromaffin and neuronal cells and thrombocytes. After release into the extracellular space, the compound affects a variety of biological activities in a wide range of target tissues. In the nervous system it acts throμgh various purinergic receptors. It also activates 5'-nucleotidase and inhibits adenosine kinase activity in vitro. Ap5A is metabolized by soluble enzymes in the blood plasma and by membrane-bound ectoenzymes of a number of cell types including endothelial and smooth muscle cells.一种二腺苷聚磷酸，储存在血小板分泌颗粒、嗜铬染色和神经细胞里。在释放进细胞外空间后，它会对靶组织产生各种生物学活性。在神经系统它通过各种嘌呤能受体起作用。在体外它能激活5′-核苷酸酶而抑制腺苷激酶活性。 A diadenosine polyphosphate stored in secretory granules of chromaffin and neuronal cells and thrombocytes. After release into the extracellular space, the compound affects a variety of biological activities in a wide range of target tissues. In the nervous system it acts through various purinergic receptors. It also activates 5'-nucleotidase and inhibits adenosine kinase activity in vitro. Ap5A is metabolized by soluble enzymes in the blood plasma and by membrane-bound ectoenzymes of a number of cell types including endothelial and smooth muscle cells.