Clostridium perfringens exotoxins. VI. Reactivity of perfringolysin O with thiol and disulfide compounds

The reactivity of perfringolysin O with thiol and disulfide compounds was studied. The activation potency of thiols was roughly proportional to the reaction rate constants of 5,5'-dithiobis-(2-nitrobenzoic acid) with thiols, which should be inversely proportional to their oxidation-reduction potentials. 1,2-Dimercaptoethane, which had the highest rate constant, most potently activated the toxin among the thiols tested and 4,4'-dipyridyl disulfide, which is known to be one of the most potent thiol-disulfide exchanging reagents, strongly inhibited toxin activity. Toxin activity was also inhibited by other thiol inhibitors.