霍乱毒素

简介组成作用机制生物活性体外研究霍乱毒素试剂级价格

霍乱毒素

CAS号:9012-63-9
英文名:CHOLERA TOXIN
中文名:霍乱毒素
CBNumber:CB0683337
分子式:NULL
分子量:0
MOL File:Mol file

霍乱毒素化学性质

储存条件 :0-6°C
溶解度 :H2O: soluble10mg/mL
形态 :lyophilized powder
颜色 :White to off-white

安全信息

危险品标志 :T
危险类别码 :24/25-52/53
安全说明 :36/37-45-61
危险品运输编号 :3172
WGK Germany :2
RTECS号 :LF3100000
危险等级 :6.1
包装类别 :I
毒性 :cholera toxin is secreted by the gram-negative bacterium Vibrio cholerae. It is a gastrointestinal toxin that increases adenylate cyclase activity of mucosa of the small intestine, thereby increasing cyclic AMP within these cells. Cyclic AMP stimulates active transport of ions by these epithelial cells, resulting in a large efflux of Na+ and water into the gut. The toxin enters cells by interacting with a GM1 ganglioside on the cell surface. After entry, the A1 subunit catalyzes the transfer of an ADP-ribose unit from NAD+ to an arginine side chain of the adenylate cyclase regulatory G protein, blocking its GTPase activity. Thus the adenylate cyclase deactivation mechanism is destroyed, and cyclic AMP is continually produced. The major sign of cholera poisoning is severe diarrhea; several liters of body water may be lost within a few hours, leading to shock and death if fluid is not replaced. Treatment involves physiological support (including i.v. fluids) and antibiotics.

霍乱毒素性质、用途与生产工艺

简介霍乱毒素是由霍乱弧菌分泌的一种蛋白质复合物，是霍乱弧菌引起严重疾病所必需的。
组成霍乱毒素由（Cholera toxin,CT）两个亚单位组成，即A亚单位（CTA）和B亚单位（CTB）。A亚单位是霍乱毒素的活性部分，B亚单位的主要功能是通过与哺乳动物小肠上皮细胞上的单唾液酸神经节苷脂GM1结合而使得A亚单位进入细胞。5个CTB与1个CTA以氢键和盐桥连接在一起，形成紧凑而稳定的AB5圆筒状六聚体蛋白。霍乱毒素被认为是最有效的口服免疫原之一。口服CT不但可以使机体产生针对CT的免疫反应，而且可以增强与CT同时给予的其他抗原的免疫反应。
作用机制
霍乱毒素可以增强肠粘膜的通透性，从而增加抗原的摄入量；
选择性诱导以Th2为主的免疫反应，从而增加特异性黏膜IgA抗体的产生；
可诱导IL-4和IL-5显著提高，而IL-2和IFN-gamma水平无明显变化。
生物活性 Cholera toxin (Choleragen) 是一种AB(5) 亚单位毒素，通过结合质膜上的神经节苷脂 GM1 进入宿主细胞，并通过跨高尔基体网络逆行进入内质网。Choleragen 通过催化促鸟嘌呤核苷酸结合蛋白 Gsα 的 ADP 核糖基化激活腺苷酸环化酶 (adenylate cyclase)。
体外研究

In the ER, a portion of Cholera toxin, the enzymatic A1-chain, is unfolded by protein disulfide isomerase and retro-translocated to the cytosol by hijacking components of the ER associated degradation pathway for misfolded proteins.
Cholera toxin acts as an ADP-ribosyltransferase to disrupt intracellular signaling in the target cell. Cholera toxin moves by vesicle carriers from the cell surface to the endoplasmic reticulum (ER) of an intoxicated cell.