DEOXYURIDYLATE KINASE ACTIVITY AND DEOXYURIDINETRIPHOSPHATASE IN ESCHERICHIA COLI

Abstract
Deoxyuridylate is phosphorylated by ATP to the deoxyuridine di- and triphosphates by enzyme fractions isolated on DEAE-cellulose columns from extracts of T2 phage-infected E. coli. The fraction from infected cells corresponds to hydroxymethyl-dCMP (deoxycytidine-5[image]-mono-phosphate) kinase and carries out phosphorylation of dTMP (deoxy-thymidine-5[image]-monophosphate) and dGMP (deoxyguanidine-5[image] mono-phosphate). It catalyzes the phosphorylation of 5-methyl-dCMP, but whether the activity on this compound and on dUMP (deoxyuridine -5[image] monophosphate) is catalyzed by hydroxymethyl-dCMP kinase is not known. An enzyme (dUTPase) purified from E. coli carries out the reaction: dUTP to dUMP and pyrophosphate. Both a mechanism for synthesizing dUTP and an enzyme to degrade this compound has been discussed in terms of the possible implication in DNA synthesis and in mutant formation.