Tryptophan content of Clostridium perfringens epsilon toxin.

The tryptophan content of Clostridium perfringens epsilon toxin was investigated. When the tryptophan content was determined by amino acid analysis after the hydrolysis of epsilon prototoxin with methanesulfonic acid containing 3-(2-aminoethyl)indole and by the spectrophotometric method with N-bromosuccinimide, the number of tryptophan residues was calculated at 1/mol of the protein. Cleavage of the prototoxin or the toxin with N-bromosuccinimide in the presence of urea gave two new fragments on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. There was only a tyrosine residue as the new N-terminal amino acid after the cleavage of the prototoxin or the toxin with N-bromosuccinimide. The data showed that epsilon prototoxin or epsilon toxin contained only one tryptophan residue.