Canalicular ectonucleoside NTPDase responsible for the main hepatic NTPDase activity. Ectonucleoside NTPDases catalyze the hydrolysis of gamma- and beta-phosphate residues of nucleotides, playing a central role in concentration of extracellular nucleotides. Has activity toward ATP, ADP, UTP and UDP, but not toward AMP. a ribonucleoside 5'-triphosphate + 2 H2O = a ribonucleoside 5'-phosphate + 2 H(+) + 2 phosphate Ca(2+) or Mg(2+). Has lower efficiency with Mg(2+). Not inhibited by ARL 67156. The transmembranous domains are involved in regulation of enzyme activity. N-glycosylated. Belongs to the GDA1/CD39 NTPase family.