In the nervous system, could hydrolyze ATP and other nucleotides to regulate purinergic neurotransmission. Hydrolyzes ADP only to a marginal extent. The order of activity with different substrates is ATP Belongs to the GDA1/CD39 NTPase family. Brain, placenta, skeletal muscle, kidney, pancreas, heart, ovary, testis, colon, small intestine, prostate and pancreas. No expression in adult thymus, spleen, lung, liver and peripheral blood leukocytes. 3 alternatively spliced human isoforms have been reported. Note: This description may include information from UniProtKB.