Subunits of RNA polymerase in function and structure. 8. Catalytic properties of self-reactivated core enzyme

Abstract

To identify the maturation pathway of Escherichia coli RNA polymerase [EC 2.7.7.6], the catalytic properties of core enzyme reactivated in the absence of maturation-promoting factors (.sigma. subunit or DNA), i.e., of self-reactivated core enzyme were compared with those of native core enzyme. Differences were found in the intrinsic activities such as in template specificity, Km value of DNA template for the polymerase, activation energy for RNA synthesis and increment of enzyme activity by .sigma. subunit. Apparently, the transcription initiation by self-reactivated core enzyme is inaccurate and, therefore, more strict conditions including the presence of maturation-promoting factors are required for premature core to be activated to the genuine function with the transcription specificity of native core enzyme.