Kwan C N, Wishnow R M
Infect Immun. 1974 Jul;10(1):146-51. doi: 10.1128/iai.10.1.146-151.1974.
A heat-labile, Pronase-sensitive factor has been partially purified from cell-free culture filtrates of enterotoxigenic Escherichia coli. The partially purified factor contains both protein and carbohydrate moieties and appears to be E. coli enterotoxin (ECT). ECT binds to cultured adrenal tumor cells rapidly and irreversibly leads to adenosine 3', 5'-cyclic monophosphate formation and steroidogenesis after a 60-min lag phase. Further studies indicate that it interacts with the cholera toxin receptor site on adrenal cells rather than the adrenocorticotropin receptor to activate adenyl cyclase. Mixed gangliosides block stimulation of steroidogenesis in response to both E. coli and cholera enterotoxin. In contrast to adrenocorticotropin, ECT has no additive effect on cholera toxin-induced steroidogenesis. The protein moiety of ECT is similar to cholera enterotoxin because horse serum anticholeragenoid prevented stimulation of steroidogenesis by either enterotoxin. Cultured adrenal cells provide a quantitative assay system that has facilitated the purification and characterization of E. coli enterotoxin.
一种对热不稳定、对链霉蛋白酶敏感的因子已从产肠毒素大肠杆菌的无细胞培养滤液中部分纯化出来。该部分纯化的因子含有蛋白质和碳水化合物部分，似乎是大肠杆菌肠毒素（ECT）。ECT与培养的肾上腺肿瘤细胞迅速结合，经过60分钟的延迟期后不可逆地导致3',5'-环磷酸腺苷形成和类固醇生成。进一步研究表明，它与肾上腺细胞上的霍乱毒素受体位点相互作用，而不是与促肾上腺皮质激素受体相互作用来激活腺苷酸环化酶。混合神经节苷脂可阻断对大肠杆菌和霍乱肠毒素的类固醇生成刺激反应。与促肾上腺皮质激素不同，ECT对霍乱毒素诱导的类固醇生成没有相加作用。ECT的蛋白质部分与霍乱肠毒素相似，因为马血清抗类霍乱原可阻止两种肠毒素对类固醇生成的刺激。培养的肾上腺细胞提供了一个定量测定系统，有助于大肠杆菌肠毒素的纯化和特性鉴定。
