title: Pyrimidine nucleotidase deficiency with active dephosphorylation of dTMP: evidence for existence of thymidine nucleotidase in human erythrocytes.
abstract: Erythrocytes from a patient with classical pyrimidine nucleotidase (PyN) deficiency had less than 10% residual PyN activity with uridine 5'-monophosphate (UMP) or cytidine 5'-monophosphate (CMP) as substrate, but exhibited brisk nucleotidase activity with thymidine 5'-monophosphate (dTMP). This strongly suggests the existence of separate enzymes or isozymes of PyN in normal human erythrocytes--an hypothesis that should be tested by similar studies in other cases of severe PyN deficiency, whether induced by genetic defects or lead toxicity.
mesh_terms: D015720:5'-Nucleotidase; D003568:Cytidine Monophosphate / Q000378:metabolism; D004905:Erythrocyte Aging; D004912:Erythrocytes / Q000032:analysis / Q000201:enzymology*; D005260:Female; D006801:Humans; D008875:Middle Aged; D009708:Nucleotidases / Q000172:deficiency*; D011742:Pyrimidine Nucleotides / Q000097:blood; D013936:Thymidine; D014542:Uridine Monophosphate / Q000378:metabolism
chemical_list: D011742:Pyrimidine Nucleotides; D014542:Uridine Monophosphate; D009708:Nucleotidases; D015720:5'-Nucleotidase; D003568:Cytidine Monophosphate; D013936:Thymidine