Purification and characterization of deoxyuridine triphosphate nucleotidohydrolase from anemic rat spleen: a trimer composition of the enzyme protein.

Deoxyuridine triphosphate nucleotidohydrolase (dUTPase) was purified to near homogeneity from the spleens of rats made anemic by phenylhydrazine injection; the enzyme activity in these spleens was about 30 times higher than that in spleens of untreated rats. The purified enzyme preparation showed an apparent molecular weight of 58,500 and appeared to consist of three identical subunits each with a molecular weight of about 19,500. The purified enzyme catalyzed specifically the hydrolysis of dUTP, and no other naturally occurring nucleoside triphosphates could be hydrolyzed by this enzyme. The Km value for dUTP was 12 microM. Enzyme activity was inhibited by the addition of EDTA, whereas the enzyme preparation exhibited activity in the absence of added divalent cations. Activity was not affected by the addition of fluoride ion.