Taketa K, Izumi M, Ichikawa E
Ann N Y Acad Sci. 1983;417:61-8. doi: 10.1111/j.1749-6632.1983.tb32849.x.
Resolution of human alpha-fetoprotein (AFP) into four distinct molecular species was demonstrated by a combination of two affinity chromatographies with crossed-immuno-affino-electrophoresis (CIAE) using concanavalin A (Con A) and Lens culinaris hemagglutinin (LcH)-A and LcH-B as affinity media. Of the four AFPs, AFP1 had no affinity for Con A, LcH-A, or LcH-B; AFP2 showed a high affinity for Con A, a low affinity for LcH-A, and an intermediate affinity for LcH-B (or a low affinity, depending on the lot of LcH-B preparations used); AFP3 revealed strong affinities for all of the three lectins; and AFP4, a trace component of hepatoma AFP in the present study, showed no interaction with Con A, but a definite interaction with LcH-A or LcH-B. These results were based on the determination of dissociation constants (Kd) of AFP-lectin complex by CIAE on isolated preparations of the three major hepatoma AFPs. These AFPs had identical electrophoretic mobilities of 0.86-0.87 (relative to human albumin) in the absence of lectins. The calculated mobilities of AFP2 and AFP3 were both reduced to 0.50-0.58 by saturation with lectins, but these two AFPs were clearly separated by 1 mg/ml LcH-A or LcH-B because of their large differences in Kd.
通过结合两种亲和色谱法和交叉免疫亲和电泳（CIAE），以伴刀豆球蛋白A（Con A）、菜豆凝集素（LcH）-A和LcH-B作为亲和介质，证明了人甲胎蛋白（AFP）可分离为四种不同的分子种类。在这四种AFP中，AFP1对Con A、LcH-A或LcH-B均无亲和力；AFP2对Con A表现出高亲和力，对LcH-A表现出低亲和力，对LcH-B表现出中等亲和力（或低亲和力，取决于所用LcH-B制剂的批次）；AFP3对所有三种凝集素均表现出强亲和力；而AFP4，在本研究中为肝癌AFP的微量成分，与Con A无相互作用，但与LcH-A或LcH-B有明确的相互作用。这些结果基于通过CIAE对三种主要肝癌AFP的分离制剂测定AFP-凝集素复合物的解离常数（Kd）。在没有凝集素的情况下，这些AFP的电泳迁移率相同，为0.86 - 0.87（相对于人白蛋白）。通过凝集素饱和，AFP2和AFP3的计算迁移率均降至0.50 - 0.58，但由于它们的Kd差异很大，这两种AFP在1 mg/ml LcH-A或LcH-B作用下能被清晰分离。
