Mechanism of Tryptic Activation ofClostridium botulinumType E Toxin

Abstract

The toxic peptide of trypsin-actlvated Clostridium botulinum type E was purified by chromatography through columns packed with Sephadex G-75 and G-50. The molecular weight of the active peptide was estimated to lie between 10,000 and 12,000. Amino acid analyses indicated that the active peptide had lost at least 18 of the amino acid residues present in the original protein. The active peptide and the original protein were found to have different N-terminal amino acid residues. The mechanism of tryptic activation apparently involves chiefly the removal of amino acids from the N-terminus of the toxin molecule.