title: DNA polymerases of murine LBN/b leukemic cells.
abstract: In the post-mitochondrial fraction of murine LBN/b leukemic cells, four fractions with DNA polymerase activity (I, II, III, IV) were found. On the basis of ion exchanger affinity and poly(A), poly(C) and poly(Cm) replication ability, fraction I was classified as RNA-directed DNA polymerase of viral origin. On the basis of the differences in the ion exchanger affinity, molecular weight, template requirement, pH-dependence of enzymatic activity and NaCl concentration, divalent ion requirements and susceptibility to N-ethylmaleimide inhibition, fractions II, III and IV were classified as DNA-directed DNA polymerases beta, alpha and gamma, respectively. Three fractions, i.e. reverse transcriptase, and DNA-directed DNA polymerases beta and gamma,  were found to incorporate dTMP on a poly(A)-oligo(dT) template-primer. Despite the similarity of the reaction of DNA polymerases beta and gamma with poly(A)-oligo(dT), some other properties of these enzymes suggest that they represent distinct enzymatic entities.
mesh_terms: D000818:Animals; D004254:DNA Nucleotidyltransferases / Q000302:isolation & purification / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007942:Leukemia, Experimental / Q000201:enzymology*; D008274:Magnesium / Q000494:pharmacology; D008345:Manganese / Q000494:pharmacology; D051379:Mice; D008815:Mice, Inbred Strains; D008970:Molecular Weight; D012194:RNA-Directed DNA Polymerase / Q000302:isolation & purification / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology; D013347:Subcellular Fractions / Q000201:enzymology; D013698:Templates, Genetic
chemical_list: D008345:Manganese; D012965:Sodium Chloride; D004254:DNA Nucleotidyltransferases; D012194:RNA-Directed DNA Polymerase; D008274:Magnesium