CHARACTERIZATION OF MAMMALIAN DNASE V, A DOUBLE-STRAND BIDIRECTIONAL EXONUCLEASE WHICH INTERACTS WITH DNA POLYMERASE-β OF THE NOVIKOFF HEPATOMA

ABSTRACT Novikoff hepatoma factor IV, a protein identified by its ability to stimulate the β-polymerase, has now been purified to homogeneity. This 12,000 dalton polypeptide has both 3′→′ and 5′→3′ exonuclease activity on double-stranded substrates and forms a specific complex with the β-polymerase in a 1:1 stoichiometry. Some of the properties of this enzyme are described. Since this enzyme differs from other mammalian nucleases, we have named it DNase V.