Pyrophosphatase that hydrolyzes non-canonical purine nucleotides such as inosine triphosphate (ITP), deoxyinosine triphosphate (dITP) or xanthosine 5'-triphosphate (XTP) to their respective monophosphate derivatives. The enzyme does not distinguish between the deoxy- and ribose forms. Probably excludes non-canonical purines from RNA and DNA precursor pools, thus preventing their incorporation into RNA and DNA and avoiding chromosomal lesions. a ribonucleoside 5'-triphosphate + H2O = a ribonucleoside 5'-phosphate + diphosphate + H(+) a 2'-deoxyribonucleoside 5'-triphosphate + H2O = a 2'-deoxyribonucleoside 5'-phosphate + diphosphate + H(+) H2O + ITP = diphosphate + H(+) + IMP dITP + H2O = dIMP + diphosphate + H(+) H2O + XTP = diphosphate + H(+) + XMP Binds 1 divalent metal cation per subunit; can use either Mg(2+) or Mn(2+). Homodimer. Belongs to the HAM1 NTPase family. Extended N-terminus. Extended N-terminus.