Ohtomo N, Muraoka T, Tashiro A, Zinnaka Y, Amako K
J Infect Dis. 1976 Mar;133 Suppl:31-40. doi: 10.1093/infdis/133.supplement_1.s31.
Cholera toxin (choleragen) dissociated into two types of subunit with molecular weights estimated to be 28,000 daltons (A) and 11,000 daltons (B); this dissociation was effected by gel filtration at acid pH with or without urea. Subunit A could be separated into two fragments, A1 (23,000 daltons) and A2 (about 2,500 daltons), after reduction and alkylation. Choleragenoid (68,000 daltons) appeared to be a polymerized form of subunit B. A-specific antigen was found in choleragen as well as in A1 and A2, while B-specific antigen was found in both choleragen and choleragenoid. In electron micrographs, the toxin molecule appeared as a particle of uniform size consisting of subunits in V- or Y-shape and in ring form. The dimensions coincided with the values calculated from the molecular weights.
霍乱毒素（霍乱原）可解离为两种亚基，分子量估计分别为28,000道尔顿（A）和11,000道尔顿（B）；这种解离可通过在酸性pH值下进行凝胶过滤来实现，有无尿素均可。在还原和烷基化后，亚基A可分离为两个片段，A1（23,000道尔顿）和A2（约2,500道尔顿）。类霍乱原（68,000道尔顿）似乎是亚基B的聚合形式。在霍乱毒素以及A1和A2中均发现了A特异性抗原，而在霍乱毒素和类霍乱原中均发现了B特异性抗原。在电子显微镜照片中，毒素分子呈现为大小均匀的颗粒，由呈V形或Y形以及环形的亚基组成。其尺寸与根据分子量计算的值相符。
