Absence of low molecular weight DNA polymerase activity from the nuclei of Amoeba discoides.

Amoeba discoides nuclear protein partially purified by passage through Sephadex G-200 showed 3 high-mol.-wt. DNA polymerase activities which eluted in and just following the void volume. No low-mol.-wt (45,000 daltons) DNA polymerase beta activity was detected. Nuclear protein layered on 5--20% sucrose gradients also showed an absence of low-mol.-wt DNA polymerase beta. The void volume enzyme showed deoxyribonuclease activity, but no low-mol.-wt nuclease activity was detected.