Comparison of beta-Galactosidases from Normal and Operator Constitutive Strains of E. Coli

This brief article, Steers, Craven, and Anfinsen reported the results of various physical and chemical studies involving enzymatic comparisons of the lactose splitting enzyme beta-galactosidases from the "normal," or "wild type," and "operator constitutive" strains of E. coli. They determined that no detectable differences could be found between the two protein preparations, and concluded that the operator locus, the region of DNA at one end of an operon that acts as the binding site for repressor proteins, did not specify any part of the structure of the beta-galactosidase molecule.