Properties of soluble DNA polymerase from sera of hepatitis B virus carriers

A soluble DNA polymerase was purified 8,000-fold from hepatitis B surface antigen positive serum. The molecular weight of the enzyme by gel filtration was about 1.60 X 10(5), the sedimentation coefficient was 5.5S, the apparent Km for dTTP was 4 micrometer, the optimum pH in the presence of Mg2+ was 9.2, and the pl was 4.7. The enzyme was found in HBsAg-positive sera and required an external primer for activity. The properties of the DNA polymerase were different from hepatitis B virus particle enzyme and from vertebrate and bacterial DNA polymerases. The prevalence of this enzyme did not correlate with HBeAg or particle DNA polymerase in HBsAg-positive sera.