title: Isolation and characterization of the heat stable enterotoxin from a pathogenic bovine strain of Escherichia coli.
abstract: A heat-stable enterotoxin secreted by a pathogenic strain of Escherichia coli of calf origin was purified to homogeneity by a procedure involving acetone fractionation, DEAE cellulose chromatography, Biogel P2 chromatography and size exclusion high pressure liquid chromatography. The purity of the product was ascertained by amino-acid analyses and amino acid sequence using manual degradation with 4-N, N dimethylaminoazobenzene-4' isothiocyanate (DABITC) and an automatic gas phase sequenator. The following amino acid sequence is proposed: Asn-Thr-Phe-Tyr-Cys-Cys-Glu-Leu-Cys-Cys-Asn-Pro-Ala-Cys-Ala-Gly-Cys-Tyr. It is identical to a similar active peptide isolated from strains of porcine origin. Antibodies to ST were successfully produced in rabbits using a conjugate with bovine serum albumin. The ultraviolet absorption and circular dichroism spectra of the active product were recorded and discussed.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000992:Antitoxins / Q000276:immunology; D001427:Bacterial Toxins / Q000032:analysis / Q000276:immunology / Q000302:isolation & purification*; D002417:Cattle; D005591:Chemical Fractionation; D002848:Chromatography, DEAE-Cellulose; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D004768:Enterotoxins / Q000032:analysis / Q000276:immunology / Q000302:isolation & purification*; D004926:Escherichia coli; D029968:Escherichia coli Proteins; D051379:Mice; D011817:Rabbits; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000992:Antitoxins; D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; C034151:heat stable toxin (E coli)