MOLECULAR SIZE OF CLOSTRIDIUM BOTULINUM TYPE E TOXIN IN ^|^ldquo;IZUSHI^|^rdquo;

Abstract

Botulogenic “izushi” was prepared from flounders inoculated with spores of Clostridium botulinum type E by the method commonly practiced in the local areas. To determine the molecular size and the properties of the toxin in “izushi, ” the exudate of the “izushi” and the extract of the fish were subjected to gel filtration on Sephadex G-100 and ultracentrifugal separation in sucrose density gradient. Most of the toxin in “izushi” was proved to be in the form of precursor and to possess a large molecular size with a sedimentation constant (S20⋅ W) of about 11.5. The tryptic activation of the precursor in the “izushi” caused no appreciable reduction in the molecular size.