Theta-toxin of Clostridium perfringens I. purification and some properties

Abstract

θ-Toxin, an oxygen-labile bemolysin produced by Clostridium perfringens, was purified 3300 fold from culture filtrate by successive chromatography on DEAE-Sephadex A-50 and Sephadex G-150. The purified toxin gave two distinct bands in disc electrophoresis, while the same material, after mild reduction with dithiothreitol, yielded a single band, indicating that the purified θ-toxin contained, as well as a reduced, active form, an oxidized, inactive form of toxin. These two forms of the toxin had a similar, if not identical molecular size. The purified preparation gave a single band in sodium dodecyl sulfate polyacrylamide gel electrophoresis and formed a single precipitin line with National Standard gas gangrene ( C. perfringens) antitoxin. By sodium dodecyl sulfate polyacrylamide gel electrophoresis, the molecular weight of θ-toxin was estimated to be 51 000, the value being in exact accordance with that obtained by amino acid analysis. The amino acid composition of θ-toxin was very close to that of cereolysin, an oxygen-labile hemolysin produced by Bacillus cereus. The amino-terminal residue of θ-toxin was lysine as determined by the Dansyl method.