On the Rule of Different Subunits of DNA-Dependent RNA Polymerase from E. coli in the Transcription Process
This extract was created in the absence of an abstract.
Excerpt
DNA-dependent RNA polymerase from E. coli is now routinely obtained in our laboratory in a highly purified form (more than 95% pure) in large quantities (up to 300 mg/kg cell wet weight) by two alternative procedures. The first one involves the use of polymin P for the precipitation of the enzyme from the crude extract, DEAE chromatography, ammonium sulfate precipitation, and two zonal centrifugation steps performed at different ionic strength for the isolation of a full enzyme which contains about 50% of the stoichiometrically saturating amount of initiation factor σ (Zillig et al., 1970). The second procedure involves phosphorylcellulose (PC) chromatography (Burgess et al., 1969) following the DEAE step of the first procedure, which yields minimal or core enzyme. From the flow-through of the PC column, another DEAE step and sucrose gradient sedimentation yield purified initiation factor σ.
The enzyme has been dissociated into its subunits β′, β, 2 ×...
