An improved method for the purification of DNA-dependent RNA polymerase from Escherichia coli.

DNA-dependent RNA polymerase from Escherichia coli was purified further by elution through heparin-Sepharose CL-6B column after the enzyme was obtained, partially purified, using Burgess and Jendrisak's method [(1975)Biochemistry 14, 4634] The total yield of the pure protein was 10 mg from 50 g of E.coli cells. The method was found to be very reproducible and convenient. The enzyme preparation had 60% active molecules and the elongation rate of RNA synthesis by this enzyme was measured to be 11 bases/s over delta D111 T7 DNA.