Separation and Purification of Enterotoxins From a Strain Escherichia Coli Pathogenic for Pigs

Enterotoxin was produced by growing Escherichia coli strain PI6 (serotype 09; K9) in a defined medium. Ultrafiltration and gel-filtration studies suggested that toxic activity was produced by enterotoxins, 17, 27, 33 and 17% of which had, respectively, MW values of 5·9 × 105, 9·5 × HP, 6·7 × 103 and 380. Inactivation accounted for the remaining 6%. There was some evidence that toxin of MW 6·7 × 103 fragmented to produce toxin of MW 380.