[Molecular weight and size of the molecules of immunologically separate Shigella sonnei colicine types].

Biologically active electrophoretically homogeneous fractions of Sh. sonnei colicines (isolated by gel-chromatographic distribution on Sephadex) were characterized within the range of each of the immunologically isolated type by constant values of the molecular weight and the molecule size and also by close specific activity values. Immunologically nonhomogeneous types of colicines produced by Sh. sonnei differed considerably by their molecular-weight characteristics, the size of the molecules and the specific activity. The detected identity of the absorption spectra in the ultraviolet region of different types of colicines could point to the commonness of the structural elements of their protein molecules.