Purification and characteristics of the enterotoxin of Clostridium perfringens type A

Abstract

Enterotoxin was extracted from sporulated cells of Clostridium perfringens type A and purified by gel and ion exchange chromatography. A single protein band was obtained after electrophoresis of the toxin on cellulose polyacetate, and a single precipitin line after immunodiffusion against crude antiserum. Disc gel electrophoresis resulted in the resolution of the toxin into one major and two accessory bands, all biologically active, and into a few faint bands which had no measurable biological activity and constituted less than 3% of the total protein. The two accessory enterotoxin bands appeared to be derived from the major band as a result of ion exchange chromatography.The ultraviolet absorption spectrum of the purified enterotoxin was characteristic for proteins. The toxin was essentially free of nucleic acids, fatty acids, lipid phosphorus, and reducing carbohydrates. Its apparent molecular weight was 36 000 ± 4000, the Stokes radius was 2.6 mμ, and the isoelectric point was at pH 4.3. The purified toxin was enterotoxic in ligated intestinal loops of rabbits and had a specific toxicity of about 2000 mouse MLD/mg N.