The inactivation of Clostridium perfringens epsilon toxin by treatment with tetranitromethane and N-acetylimidazole.

When one residue of tyrosine per molecule of epsilon toxin was nitrated by tetranitromethane, the modified toxin lost more than 90% of its original activity. The toxin also was inactivated by treatment with N-acetylimidazole. The lethality was restored when the inactive N-acetylimidazole-treated toxin was treated with hydroxylamine. The inactive N-acetylimidazole-treated toxin was not nitrated by tetranitromethane under conditions where one residue of Tyr per molecule of the untreated toxin is nitrated. These data suggest that only one Tyr residue in the toxin is important for the lethal activity.