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 (By similarity). 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+). Present in liver, and at lower level in jejunum and kidney. Limited to the canalicular domain of hepatocytes (at protein level). The transmembranous domains are involved in regulation of enzyme activity. N-glycosylated. Belongs to the GDA1/CD39 NTPase family.