Drosophila deoxyuridine triphosphatase. Purification and characterization.

Deoxyuridine triphosphatase (dUTPase), an enzyme that catalyzes hydrolysis of dUTP to deoxyuridylate and inorganic pyrophosphate, has been purified approximately 6,000-fold from Drosophila embryos. The enzyme has a native molecular weight of 46,000 and a sedimentation coefficient of 3.5 S. The enzyme is most likely a metalloenzyme. It is specific for dUTP among the DNA nucleotides tested, with an apparent Km of 1 microM. The expression of dUTPase appears stage-specific, with embryos representing the only step in the life cycle of Drosophila with clearly detectable levels of the enzyme. While other possibilities exist, these results suggest an enhanced opportunity for the inclusion of uracil into Drosophila DNA subsequent to embryonic development.