Hydrolyzes PPi generated in anabolic reactions. Catalyzes the hydrolysis of inorganic pyrophosphate (PPi) forming two phosphate ions. diphosphate + H2O = H(+) + 2 phosphate In the presence of Zn(2+) ions, activity is 13% of maximum, in the presence of Mn(2+), Cu(2+), Fe(2+) or Co(2+) ions, activity is very low. In the absence of metal ions, there is no activity. Inhibited by ATP, but not by fructose 1,6-bisphosphate or 2-phosphoglycerate. Homohexamer. Belongs to the PPase family. Truncated N-terminus.