Cleaves P(1)-P(3)-bis(5'-adenosyl) triphosphate (Ap3A) to yield AMP and ADP. Can also hydrolyze P(1)-P(4)-bis(5'-adenosyl) tetraphosphate (Ap4A), but has extremely low activity with ATP. Modulates transcriptional activation by CTNNB1 and thereby contributes to regulate the expression of genes essential for cell proliferation and survival. Plays a role in the induction of apoptosis via p53/TP53, SRC and AKT1 signaling pathways. Induction of apoptosis depends on the ability of FHIT to bind P(1)-P(3)-bis(5'-adenosyl) triphosphate or related compounds, but does not require its catalytic activity (By similarity). H2O + P(1),P(3)-bis(5'-adenosyl) triphosphate = ADP + AMP + 2 H(+) Divalent metal cations. Mg(2+) or Mn(2+). Homodimer.