Interconversion of Molecular Size of the DNA Polymerase from Rauscher Leukemia Virus

DNA polymerase was purified about 150-fold from Rauscher leukemia virus (RLV) by repeated chromatography on DEAE-Sephadex A-50 with a gradient elution of 0–1.0 m KCl. The DNA polymerase purified under the mild condition of extraction and purification is an aggregate enzyme which can exist in the form of 480,000 daltons molecular weight. This polymerase is converted to 135,000- and 70,000-dalton molecules when the enzyme is exposed to salt (0.5 m KCl). A species of 70,000 daltons molecular weight is the minimum size of the enzyme’s active form. Removal of the salt by gel filtration permits reversibility to the high molecular weight molecule. When measured by electrophoresis in a gel of 5% polyacrylamide containing 0.1% sodium dodecyl sulfate, the subunit constituent of the purified RLV-DNA polymerase showed one kind of polypeptide with a molecular weight of 26,000 daltons.