Separation of Clostridium botulinum type A derivative toxin into two fragments

Two fragments with molecular weights of 105,000 (fragment I) and 58,000 (fragment II) were separated chromatographically from each other after Clostridium botulinum type A derivative toxin adsorbed onto a QAE-Sephadex column was treated with dithiothreitol and urea. They were antigenic and formed crossing precipitin lines against anti-derivative toxin in agar gel diffusion tests. Upon removal of dithiothreitol and urea by dialysis, the two fragments reassembled to reconstruct the derivative toxin molecule.