. "Also acts on bis(5'-guanosyl) tetraphosphate and bis(5'-adenosyl) pentaphosphate, and, more slowly, on some other polyphosphates, forming a nucleoside bisphosphate as one product in all cases (cf. EC 3.6.1.17)." . . . "Bis(5'-nucleosyl)-tetraphosphatase (symmetrical)" . "Diadenosinetetraphosphatase (symmetrical)" . "Dinucleosidetetraphosphatase (symmetrical)" . "Ap(4)A hydrolase" . "Ap4A hydrolase" . "Diadenosine 5',5'''-P(1),P(4)-tetraphosphate pyrophosphohydrolase" . "P(1),P(4)-bis(5'-adenosyl) tetraphosphate + H(2)O = 2 ADP." .