Purification and Some Properties of Progenitor Toxins of Clostridium botulinum Type B

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Abstract
Purification of progenitor toxin of Clostridium botulinum type B strain Okra was undertaken by sequential steps of acid precipitation, extraction, ammonium sulfate precipitation, ribonuclease digestion, acid precipitation, protamine treatment, sulphopropyl-Sephadex chromatography, and Sephadex G-200 gel filtration. Two different molecular-sized toxins, named large (L) and medium (M) toxins, were obtained. L toxin was centrifugally homogeneous but electrophoretically heterogeneous. It contained 2.5 × 10 8 to 3.0 × 10 8 mean lethal doses per mg of nitrogen, and its sedimentation constant was 16 S . M toxin was centrifugally and electrophoretically homogeneous. It contained 5.5 × 10 8 to 6.0 × 10 8 mean lethal doses per mg of nitrogen, and its sedimentation constant was 12 S . The presence of both L and M toxins in spent culture was demonstrated. It seems justified, therefore, to call both progenitor toxins. Both consisted of toxic and nontoxic components. The toxic components of L and M toxins appeared to be identical with each other. The nontoxic component of L toxin was 12 S and possessed a hemagglutinin activity of about 0.5% that of type A crystalline toxin; that of M toxin was 7 S and possessed no hemagglutinin activity. They were antigenically related but not identical.