title: Purification of the polymyxin-released, heat-labile enterotoxin of Escherichia coli.
abstract: The heat-labile enterotoxin of Escherichia coli strain H-10407 has been purified by use of a commercially available affinity gel (Affi-Gel 202). This gel possesses a strong and highly specific affinity for the enterotoxin released from intact E. coli cells by polymyxin B. The polymyxin-release technique could be used with fermenter-size batches of E. coli cells grown in a casamino acids-yeast extract medium. With a simple (NH4)2SO4 back-extraction step prior to affinity chromatography, large batches of E. coli enterotoxin could be processed rapidly. Affi-Gel 202-purified E. coli enterotoxin produced a single precipitin band in the presence of several different antisera against crude preparations of the toxin. The same antigen produced a precipitin band in the presence of both cholera antitoxin and antiserum to choleragenoid.
mesh_terms: D000942:Antigens, Bacterial; D001426:Bacterial Proteins / Q000302:isolation & purification; D002846:Chromatography, Affinity; D004768:Enterotoxins / Q000032:analysis / Q000302:isolation & purification*; D004926:Escherichia coli / Q000276:immunology; D006358:Hot Temperature; D007122:Immunoelectrophoresis; D008722:Methods; D011113:Polymyxins
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D004768:Enterotoxins; D011113:Polymyxins