title: Partial purification and characterization of heat-stable enterotoxin produced by Yersinia enterocolitica.
abstract: By using a suckling mouse assay, heat-stable enterotoxin (ST) was purified from the culture filtrate of Yersinia enterocolitica isolated from a diarrheal patient. The purification procedures involve ultrafiltration with an Amicon HIP-10 hollow fiber, ethanol fractionation, protamine sulfate treatment, diethylaminoethyl-Sephacel and hydroxylapatite column chromatographies, and Sephacryl S-200 superfine gel filtration. About 408-fold purification was achieved, with a yield of 12.0%. The minimal effective dose of purified ST was about 110 ng in the suckling mouse assay. The molecular weight of purified ST was 9,000 by Sephadex G-100 superfine gel filtration. The purified ST was stable to heating (100 degrees C for 20 min, 121 degrees C for 20 min) and did not lose its toxicity after treatment with protease, trypsin, lipase, phospholipase C, ribonuclease, deoxyribonuclease, beta-glucosidase, and neuraminidase. The purified ST was separated by isoelectric focusing into two active fractions, with pI's of 3.29 (ST-1) and 3.00 (ST-2), respectively. Antiserum from guinea pigs immunized with the purified ST neutralized the activity of both Y. enterocolitica ST and Escherichia coli ST.
mesh_terms: D001427:Bacterial Toxins / Q000276:immunology / Q000302:isolation & purification*; D001681:Biological Assay; D003429:Cross Reactions; D004768:Enterotoxins / Q000276:immunology / Q000302:isolation & purification*; D006358:Hot Temperature; D007526:Isoelectric Point; D008970:Molecular Weight; D015007:Yersinia / Q000032:analysis* / Q000276:immunology
chemical_list: D001427:Bacterial Toxins; D004768:Enterotoxins