VIBRIO-CHOLERAE CHOLERAGENOID - MECHANISM OF INHIBITION OF CHOLERA TOXIN ACTION
VIBRIO-CHOLERAE CHOLERAGENOID - MECHANISM OF INHIBITION OF CHOLERA TOXIN ACTION
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DOI：
10.1021/bi00742a034
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发表时间：
1973-01-01
期刊：
影响因子：
2.9
通讯作者：
CUATRECA.P
中科院分区：
文献类型：
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作者：
CUATRECA.P
类霍乱弧菌是一种从霍乱弧菌的外毒素中提取的无生物活性蛋白，它能像母体毒素一样有效地阻止125i标记的霍乱毒素与肝膜的结合。125i标记的霍乱毒素与类霍乱弧菌孵育并随后洗涤的膜的结合受到的抑制程度与用霍乱毒素孵育的膜相同。霍乱毒素-膜复合物的解离率无论在霍乱毒素或类霍乱杆菌存在下测量都是相同的。类霍乱素在分离的脂肪细胞中不会引起脂溶反应。当细胞与类霍乱素在24小时内预孵育15分钟时，对霍乱毒素诱导的脂肪分解有有效的抑制作用。0.2/xg/ml霍乱毒素要抑制50%的脂溶反应所需的类霍乱素浓度约为40 ng/ml （7 × 10-10 m）。如果首先将脂肪细胞与霍乱毒素孵育（15分钟，24分钟），类霍乱素几乎没有抑制作用。类霍乱素阻断霍乱毒素的脂溶活性的能力可以解释为它能够通过自身占据膜受体来阻断毒素与膜受体的结合
Choleragenoid, a biologically inactive protein which is derived from the exotoxin of Vibrio cholerae, blocks the binding of 125I-labeled cholera toxin to liver mem-branes as effectively as the parent toxin. The binding of 125I-labeled cholera toxin to membranes which have been incu-bated with choleragenoid and subsequently washed is sup-pressed to the same extent as when the membranes are incu-bated with cholera toxin. The rate of dissociation of the cholera toxin-membrane complex is the same whether it is measured in the presence of cholera toxin or of choleragenoid. Choleragenoid does not elicit a lipolytic response in isolated fat cells. When the cells are preincubated for 15 min at 24 with choleragenoid, there is potent inhibitionof cholera toxin induced lipolysis. The concentration of choleragenoid re-quired to inhibit by 50% the lipolytic response of 0.2/xg/ml of cholera toxin is about 40 ng/ml (7 X 10-10 m). Choleragenoid exhibits virtually no inhibitory effect if the fat cells are in-cubated (15 min, 24) first with cholera toxin. The abilityof choleragenoid to block the lipolytic activity of cholera toxin is explicable in terms of its ability to block the binding of the toxin to the membrane receptor by its own occupancy of that