Description_x000D_ General description_x000D_ DNA polymerase I (holoenzyme) has 5′→3′ and 3′→5′ exonuclease activities in addition to its synthetic activity. This bifunctional activity enables the enzyme to use nicks or gaps in double stranded DNA as starting points for DNA synthesis. The 5′→3′ exonuclease activity degrades the DNA strand complementary to the template strand beginning at the nick. DNA synthesis begins at the 3′-end of the nick and produces a new strand of DNA complementary to the template. The net result is the movement of the polymerase along the template strand (nick translation) until the DNA complementary to the template (from the site of the original nick to the 5′-end of the template strand) is replaced._x000D_ Application_x000D_ DNA Polymerase I from Escherichia coli has been used to study the effects of the anti-tumor drug cis-diaminedichloroplatinum (II) on the enzyme activity._x000D_ Components_x000D_ DNase Polymerase I is supplied in a solution of 50% glycerol containing 100 mM potassium phosphate buffer (pH 6.5), and 1 mM dithiothreitol._x000D_ Unit Definition_x000D_ One unit converts 10 nanomoles of deoxyribonucleoside triphosphates into acid insoluble material in 30 min at 37 °C.