A method of isolation and properties of DNA-dependent DNA-polymerase epsilon from human placenta]

DNA polymerase epsilon was purified to near homogeneity from human placenta. The enzyme has one subunit (170 kDa, sedimentation coefficient 8.2S), intrinsic 3'-5'-exonuclease activity, it is independent on PCNA and high processivity on poly(dA)-oligo(dT) template-primer without PCNA. It was shown, that the enzyme incorporates 3'-amino-2',3'-dideoxythymidine 5'-triphosphate in DNA, after that synthesis is stopped. Simultaneously DNA polymerase alpha was purified.