破伤风毒素（TT）是由破伤风杆菌产生的一种神经毒素,其分子量为150kDa,含有一条50kDa的轻链和一条100kDa的重链,轻链在氨基端以二硫键与重链相连。重链的羧基端有一个50kDa的C片段,该片段具有神经节苷脂及蛋白结合活性。轻链为锌依赖性蛋白酶,能通过蛋白酶解小突触泡蛋白而阻断神经元释放抑制物。用大肠杆菌、酵母细胞或培养的昆虫细胞表达的重组C片段,纯化 Tetanus toxin (TT), a neurotoxin produced by Clostridium tetani, has a molecular weight of 150 kDa and contains a light chain of 50 kDa and a heavy chain of 100 kDa. The light chain is disulfide bonded to the heavy chain at the amino terminus. The carboxyl terminus of the heavy chain has a 50 kDa C fragment, which has ganglioside and protein binding activity. The light chain is a zinc-dependent protease that blocks neuronal release inhibitors by proteolytic synaptobrevin. Recombinant C fragments expressed in E. coli, yeast cells or cultured insect cells were purified