Exhibits pyrophosphatase activity with stronger affinity for pyrophosphate (PPi), moderate affinity for ATP and ADP, and weak affinity for tripolyphosphate (PPPi). No activity observed toward uridine substrate. Regulates positively natural and dark-induced leaf senescence. diphosphate + H2O = H(+) + 2 phosphate Optimum pH is 8-9. Ubiquitously expressed in all tissues, with strong expression detected in senescent leaves. Accumulates during leaf senescence. Delayed dark-induced and natural senescence.