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Abstract

Investigations have been made on the purification of Clostridium botulinum type E toxin and an attempt made to elucidate the phenomenon of trypsin activation. Type E botulinus toxin produced in meat infusion medium in dialysis sacs was partially purified by Seitz filtration and ethanol precipitation. Treatment of this toxic preparation with trypsin produced a 20 - 50 fold increase in potency. Both non-activated and trypsin-activated toxins were further purified by elution through cellulose ion-exchange columns and dried by lyophilization. Refractionation of these dried toxins effected even further purity. These highly purified preparations of both non-activated and trypsin-activated type E toxin were then analysed in the ultracentrifuge. The former was found to have a sedimentation constant of 5.6 Svedburg units whereas activated toxin did not form a boundary under identical conditions. Together with other considerations, this evidence indicates that the activation mechanism involves a fragmentation process whereby more toxic sites become exposed on the toxin molecule.