Purification of Thermus aquaticus DNA polymerase expressed in Escherichia coli

Anal Biochem. 1990 Dec;191(2):396-400. doi: 10.1016/0003-2697(90)90238-5.


DNA polymerase from Thermus aquaticus has become a common reagent in molecular biology because of its utility in DNA amplification and DNA sequencing protocols. A simplified method is described here for isolating the recombinant Taq enzyme after overproduction in Escherichia coli. Purification requires 8 to 10 h and entails heat treating and clearing the E. coli lysate, followed by precipitation of the enzyme with polyethyleneimine and elution from Bio Rex 70 ion exchange resin in a single salt step. The resulting enzyme preparation contains a single, nearly homogeneous protein consistent with the previously established size of the Taq DNA polymerase in a yield of 40-50 mg of protein per liter of cell culture.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Base Sequence
  • Chemical Precipitation
  • Chromatography, Ion Exchange
  • DNA-Directed DNA Polymerase / biosynthesis
  • DNA-Directed DNA Polymerase / genetics
  • DNA-Directed DNA Polymerase / isolation & purification*
  • Escherichia coli / enzymology
  • Escherichia coli / genetics*
  • Molecular Sequence Data
  • Plasmids
  • Polyethyleneimine
  • Recombinant Proteins / biosynthesis
  • Recombinant Proteins / isolation & purification
  • Taq Polymerase
  • Thermus / enzymology*
  • Thermus / genetics


  • Recombinant Proteins
  • Polyethyleneimine
  • Taq Polymerase
  • DNA-Directed DNA Polymerase