Beta - exotoxin is an inhibitor of rna polymerase and acts competitively with atp in various biological processes 外毒素是rna聚合酶的抑制剂，在各个生化过程中与atp起竞争作用。
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The toxin may be formed within the pathogen and released when it dies ( endotoxin ) , or secreted through its cell wall ( exotoxin ) 在病原体内形成，当病原体裂解时被释放的毒素为内毒素；由病原体通过细胞壁向外分泌的毒素为外毒素。
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Translocation from endocytic compartments to the cytosol is the essential and rate - limiting step in the intoxication process of most toxins such as ricin , diphtheria toxin , shiga toxin and pseudomonas exotoxin ( pe ) . a number of these toxins are transported to trans - golgi network ( tgn ) , and in many cases such transport to the tgn is required for the translocation and cytotoxicity . in deed , 5 % of the ricin endocytosed by cells has been shown to reach the tgn 蓖麻毒素进入细胞的机理不甚明了，一般认为是rtb先与细胞膜受体结合，主要经过受体介导的内吞作用进入吞噬体，然后沿着内体、高尔基体、内质网等逆向分泌途径，有序地运输到内质网，最后从内质网转位进入细胞浆，在胞浆内攻击核糖体，从而抑制蛋白质的合成，导致细胞死亡。
