Chemical synthesis of a highly potent and heat-stable analog of an enterotoxin produced by a human strain of enterotoxigenic Escherichia coli.

A shorter analog of a heat-stable enterotoxin produced by a human strain of enterotoxigenic Escherichia coli SK-1, consisting of 14 amino acid residues including 6 half-cystine residues, was synthesized by conventional methods. The peptide was evaluated for ability to induce intestinal secretion in suckling mice and for stability at high temperature under various conditions. The peptide was 2-5 times more potent than native toxin and was still toxic after heat-treatment at 120 degrees C for 30 min.