Action of Protease I of Escherichia coli on RNA Polymerase of Same Origin

The recently isolated protease I of Escherichia coli leads to the partial degradation of RNA polymerase of E. coli and causes, in particular, the splitting of subunits ββ′ into fragments of approximately the same size as that of factor σ. This action is similar to that of papaïn or α‐chymotrypsin employed for short periods at much lower concentrations. The immunochemical study presented leads to the identification of the origin of the fragments obtained by limited proteolysis and shown the lack of cross reaction between subunits ββ′ and σ factor.