title: Detection and purification of the free A subunit of heat-labile enterotoxin produced by enterotoxigenic Escherichia coli.
abstract: After removal of total B subunit and heat-labile enterotoxin (LT) from crude cell extracts of enterotoxigenic Escherichia coli (HB 101-EWD 299) by Bio-gel A 5 m column chromatography, the crude cell extract was shown to contain a free A subunit (A' subunit) that did not bind to the coligenoid of the B subunits. The A' subunit was found to be immunologically identical to the A subunit of holo-LT and was purified to show only one band in SDS-poly-acrylamide gel electrophoresis (PAGE). The mobility of the A' subunit was identical to that of the A subunit of holo-LT. The pI value of the A' subunit was also the same as that of the A subunit of holo-LT. These data suggest that in enterotoxigenic E. coli there is free A subunit which may be involved in formation of holo-LT, analogously to free B subunit (coligenoid), and that the free A subunit is physicochemically and immunologically identical to the A subunit of holo-LT.
authors.affiliation: Department of Microbiology, Fujita Health University School of Medicine, Toyoake Aichi, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Tsuji
authors.forename: T
authors.initials: T
authors.lastname: Honda
authors.forename: T
authors.initials: T
authors.lastname: Miwatani
authors.forename: A
authors.initials: A
authors.lastname: Miyama
mesh_terms: D001427:Bacterial Toxins / Q000276:immunology / Q000302:isolation & purification*; D002846:Chromatography, Affinity; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D004768:Enterotoxins / Q000276:immunology / Q000302:isolation & purification*; D004926:Escherichia coli / Q000472:pathogenicity*; D029968:Escherichia coli Proteins; D007106:Immune Sera; D005779:Immunodiffusion; D007525:Isoelectric Focusing; D046911:Macromolecular Substances; D008970:Molecular Weight
chemical_list: D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D007106:Immune Sera; D046911:Macromolecular Substances; C027538:heat-labile enterotoxin, E coli