Krop-Watorek A, Sedlaczek P, Lisowska E
Department of Immunochemistry, Polish Academy of Sciences, Wrocław.
Arch Immunol Ther Exp (Warsz). 1989;37(5-6):703-14.
CEA and NCA show an increased mobility in SDS-polyacrylamide gel electrophoresis if the samples are preheated in 1% SDS for 5 min at 100 degrees C. Now we found that the slow-to-fast form conversion of CEA and NCA also occurs under milder conditions and is reversible at low SDS concentration. At 100 degrees C the conversion was completed within few minutes in 0.03% SDS, while at lower temperatures it required higher SDS concentration and longer time of incubation. After the antigens were heated at 100 degrees C at 0.05% or lower SDS concentration, they showed slow reassociation at room temperature. Under conditions insufficient for the complete slow-to-fast or fast-to-slow form conversion two CEA or NCA bands were present at various proportions. No material with an intermediate mobility was detected for CEA, while a weak transient intermediate band (located closer to the fast band) was visible in some gels showing an incomplete dissociation or association of NCA. The ratio of mol. wts. of slow and fast band was approx. 2:1 for NCA and 1.5:1 for CEA. Despite some deviations from the expected mol. wt. of the presumably undissociated CEA, the results obtained supplied a support for the conclusion that the two electrophoretic forms of CEA and NCA represent the dimer-monomer interconversion.
如果样品在1%十二烷基硫酸钠（SDS）中于100℃预热5分钟，癌胚抗原（CEA）和神经细胞黏附分子（NCA）在SDS-聚丙烯酰胺凝胶电泳中显示出增加的迁移率。现在我们发现，CEA和NCA的慢-快形式转换也在较温和的条件下发生，并且在低SDS浓度下是可逆的。在100℃时，转换在0.03%SDS中几分钟内完成，而在较低温度下则需要更高的SDS浓度和更长的孵育时间。抗原在0.05%或更低SDS浓度下于100℃加热后，在室温下显示出缓慢的重新缔合。在不足以完成完全的慢-快或快-慢形式转换的条件下，会出现不同比例的两条CEA或NCA条带。对于CEA，未检测到具有中间迁移率的物质，而在一些显示NCA不完全解离或缔合的凝胶中，可见一条较弱的瞬时中间条带（位于更靠近快条带处）。NCA慢条带和快条带的分子量比约为2:1，CEA为1.5:1。尽管与推测未解离的CEA预期分子量存在一些偏差，但所得结果支持了CEA和NCA的两种电泳形式代表二聚体-单体相互转换这一结论。
