Nucleotidase which shows specific activity towards cytidine monophosphate (CMP) and 7-methylguanosine monophosphate (m(7)GMP). CMP seems to be the preferred substrate. H2O + N(7)-methyl-GMP = N(7)-methylguanosine + phosphate a ribonucleoside 5'-phosphate + H2O = a ribonucleoside + phosphate Monomer. Isoform 2 is highly expressed in the brain, heart, spleen, kidney and blood. Isoform 2 is expressed (at protein level) in the spleen, skeletal muscle and gastrointestinal epithelia. Isoform 2 is weakly expressed from 7.5 dpc and the expression level steadily increases through gestation. At 9.5 dpc and 10.5 dpc is first detected colocalizing with embryonic blood cells within the region of the septum transversum and within the cardiac chambers and dorsal aorta. At 12.5 dpc expression is found in the ventral neural tube and in the trigeminal ganglia and in the liver and dorsal root ganglia. Expression persists in the liver, dorsal root and trigeminal ganglia at 13.5 dpc and weaker expression becomes apparent in cardiac and skeletal muscle. At 16.5 dpc expression is detected in liver, myocardium, tongue, bronchial epithelium, gastrointestinal epithelium, cartilage and forebrain neuroepithelium. Belongs to the pyrimidine 5'-nucleotidase family.