Purification and some properties of Clostridium botulinum type-E toxin

Abstract To investigate the mechanism of the activation of Clostridium botulinum type-E toxin, attempts were made to improve our previous procedures for purification of the precursor by introducing a step of percolation of the cell extract through a column of CM-Sephadex. The RNA-bound precursor in the cell extract was not adsorbed, while some charged nontoxigenic proteins possessing molecular sizes similar to those of the precursor were adsorbed. The purified material behaved as a homogeneous protein in ultracentrifugation, electrophoresis and chromatography at pH below 6 with an s o 20, w of 11.6. Electrophoresis at pH above 7 and agar-gel-diffusion tests, however, demonstrated 2 distinct components. The material, whether unactivated or activated, is composed of toxigenic Eα and nontoxigenic Eβ components with the same s o 20, w of 7.3. The antigenic property of either component of the material was identical to the corresponding component of the activated material. The terms for different forms and components of type-E toxin are discussed.