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 × 105, the sedimentation coefficient was 5.5S, the apparent Km for dTTP was 4 MM, the optimum pH in the presence of Mg2+ was 9.2, and the pI 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.