Characterization of purified Epstein--Barr virus induced deoxyribonucleic acid polymerase: nucleotide turnover, processiveness, and phosphonoacetic acid sensitivity

The Epstein--Barr (EB) virus induced DNA polymerase has been further purified and characterized with respect to nucleotide turnover activity, processiveness of synthesis, and interaction with phosphonoacetic acid (PAA). The polymerase as purified through denatured DNA--cellulose chromatography was inseparable from a labile nuclease activity associated with an equally labile DNA-dependent nucleotide turnover function. The EB virus induced DNA polymerase even in the absence of detectable nuclease or nucleotide turnover activity was less processive in its synthesis than were lymphocyte alpha polymerase or procaryotic polymerases, and this processiveness decreased with increasing purity of the enzyme. PAA was shown to inhibit nucleotide incorporation by the EB virus induced DNA polymerase in the presence of nuclease-activated native DNA template in the manner of a pyrophosphate analogue. Under conditions in which the concentration of 3'-hydroxyl termini in the template was more limited, PAA was not inhibitory. PAA likewise failed to significantly decrease the processiveness and the nucleotide turnover function of the polymerase.