title: Pyrimidine-specific 5' nucleotidase activity in bovine erythrocytes: effect of phlebotomy and lead poisoning.
abstract: Erythrocyte pyrimidine-specific 5' nucleotidase (PY5'N) (E.C. 3.1.3.5) was measured in healthy, anemic, and lead-poisoned calves to determine whether low activity of PY5'N is associated with the propensity of cattle to develop basophilic stippling of erythrocytes. Low activity of PY5'N has been associated with basophilic stippling of erythrocytes in persons with inherited hemolytic anemia and with lead poisoning. A radiometric technique, using [14C]cytidine monophosphate as the substrate, was used to measured PY5'N activity. The erythrocytes from 4 healthy calves had much lower activity (mean of 7.1 +/- 1.6 nmols of [14C]cytidine monophosphate hydrolyzed/min/g of hemoglobin) than has been reported for human erythrocytes. The pH response curve of bovine PY5'N was similar to that of the human enzyme, with maximal activity around pH 7. Experimental hemorrhagic anemia in these calves increased PY5'N activity 6-to 7-fold, with peak activity occurring concomitantly with maximum reticulocytosis. Two of the calves were then given lead per os, and the PY5'N activity decreased within 24 hours to base-line values. In the 2 other calves not given lead, the PY5'N activity declined slowly, but did not reach base-line values after 14 days.
mesh_terms: D015720:5'-Nucleotidase; D000740:Anemia / Q000201:enzymology / Q000662:veterinary*; D000818:Animals; D002250:Carbon Radioisotopes; D002417:Cattle; D002418:Cattle Diseases / Q000201:enzymology*; D004912:Erythrocytes / Q000201:enzymology*; D007855:Lead Poisoning / Q000201:enzymology / Q000662:veterinary*; D008297:Male; D009708:Nucleotidases / Q000097:blood*
chemical_list: D002250:Carbon Radioisotopes; D009708:Nucleotidases; D015720:5'-Nucleotidase