Nucleotidase which shows specific activity towards cytidine monophosphate (CMP) and 7-methylguanosine monophosphate (m(7)GMP) (PubMed:24603684). CMP seems to be the preferred substrate (PubMed:15968458). H2O + N(7)-methyl-GMP = N(7)-methylguanosine + phosphate CMP + H2O = cytidine + phosphate a ribonucleoside 5'-phosphate + H2O = a ribonucleoside + phosphate Monomer. Isoforms 1, 3 and 4 are expressed in reticulocytes. Isoform 4 is hardly detectable in bone marrow and fetal liver. Isoform 2 is induced by interferon alpha in Raji cells in association with lupus inclusions. The disease is caused by variants affecting the gene represented in this entry. Belongs to the pyrimidine 5'-nucleotidase family. Truncated N-terminus.