dUTPase from the retrovirus equine infectious anemia virus: specificity, turnover and inhibition.

The kinetic properties of dUTPase from equine infectious anemia virus (EIAV) were investigated. K(M) (1.1 +/- 0.1 microM) and k(cat) (25 s(-1)) were found to be independent of pH in the neutral pH range. Above pH 8.0, K(M) increases slightly. Below pH 6.0, the enzyme is rapidly deactivated. Detergent was found to enhance activity, leaving K(M) and k(cat) unaffected. Compared to the Escherichia coli dUTPase, the EIAV enzyme is equally potent in hydrolyzing dUTP, but less specific. Inhibition of the viral enzyme by the nucleotides dTTP, dUMP and a synthetic analogue, 2'-deoxyuridine 5'-(alpha,beta-imido)triphosphate, is stronger by one order of magnitude.