[Modification of the method of extracting DNA-polymerase from E. coli]

Described earlier method of isolation of E. coli DNA-polymerase is modified. In order to decrease the possible effect of proteases on DNA-polymerase, the time of autolysis was shortened. An additional stage of precipitation by ammonium sulfate of 65-80% of saturation was introduced. Chromatography on DEAE-Sephadex A-25 revealed 4 fractions exhibiting DNA-polymerase activity. It is established that combination of certain DNA-polymerase fractions, belonging to different peaks, significantly intensifies the enzyme activity. It may be due to the formation of enzymic complexes.