Purification of Thermus aquaticus DNA polymerase expressed in Escherichia coli |
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Authors: | D R Engelke A Krikos M E Bruck D Ginsburg |
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Institution: | Department of Biological Chemistry, University of Michigan, Ann Arbor 48109. |
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Abstract: | 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. |
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