3.6.1.5 a ribonucleoside 5'-triphosphate + H2O - 3.6.1.5 ADP + 2 H2O - 3.6.1.5 ADP + H2O - 3.6.1.5 ADP + H2O very low activity 3.6.1.5 ADP + H2O hydrolysis of extracellular ADP 3.6.1.5 ADP + H2O 68% activity compared to ATP 3.6.1.5 AMP + H2O - 3.6.1.5 AMP + H2O hydrolysis of extracellular AMP, low activity 3.6.1.5 ATP + 2 H2O - 3.6.1.5 ATP + 2 H2O 100% activity