Jacks T M, Wu B J
Infect Immun. 1974 Feb;9(2):342-7. doi: 10.1128/iai.9.2.342-347.1974.
The low-molecular-weight, heat-stable type of Escherichia coli enterotoxin (ST) was obtained from sterile syncase broth filtrates of human and animal enteropathogenic E. coli strains. ST was assayed in infant mice, and it was found that this assay was specific for ST in that the high-molecular-weight, heat-labile type of E. coli exterotoxin would not cause fluid accumulation in these animals. ST was first detected in the broth of a culture of human strain 334A(015:H11) 5 h after inoculation, immediately after the log phase of growth; the highest concentration of ST occurred at 24 h after inoculation. ST was purified 13-fold by ultrafiltration and gel filtration chromatography. The purest preparation contained 15% protein and 2% carbohydrate. The mean effective dose or 1 unit dose in infant mice was 5.0 mug/mouse. The ST molecular weight was between 1,000 and 10,000, and its activity was resistant to acid, trypsin, and Pronase.
低分子量、热稳定型大肠杆菌肠毒素（ST）是从人和动物肠道致病性大肠杆菌菌株的无菌合酶肉汤滤液中获得的。在幼鼠中对ST进行检测，发现该检测方法对ST具有特异性，因为高分子量、热不稳定型大肠杆菌外毒素不会在这些动物中引起液体蓄积。在接种后5小时，即在对数生长期之后，首次在人菌株334A（O15:H11）的培养肉汤中检测到ST；ST的最高浓度出现在接种后24小时。通过超滤和凝胶过滤色谱法将ST纯化了13倍。最纯的制剂含有15%的蛋白质和2%的碳水化合物。幼鼠中的平均有效剂量或1单位剂量为5.0微克/只小鼠。ST的分子量在1000至10000之间，其活性对酸、胰蛋白酶和链霉蛋白酶具有抗性。
