Its molecular weight is about 84KD. It is composed of one A subunit(CTA) and five same B subunits(CTB). CTA is the toxic subunit, CTB are the nontoxic subunits and the main protective antigen of Cholera.

• CT是霍乱弧菌主要的致病因子，它是分子量为84KD的肠毒素，由1个A亚单位(Cholera toxin Asubunit，CTA)和5个B亚单位(Cholera toxin B subunit，CTB)形成的五聚体共价连接而成，CTA为毒性亚单位，CTB为无毒的受体结合亚单位，后者是霍乱的主要保护性抗原。