[Isolation and characteristics of the thermolabile enterotoxin from Escherichia coli strain H74-114].

The modified method for isolation and purification of LT-enterotoxin from Escherichia coli strain H74-114 has been proposed. Modification is based on exclusion of concentration of bacterial cell lysates by 3-5 fold dilution and changing PH during chromatography. The proposed modification permitted to increase the yield of purified and active product 8-10 fold. The obtained preparations are homogenic due to PAAG-SDS data and immunochemical analysis. B-component of TL-enterotoxin is shown to consist of 4 subunits B in contrast to B-component of choleragen, consisting of 5 subunits. The mol mass of A component of both toxins is identical but in contrast to choleragen the component of LT-enterotoxin is not subject to proteolysis.