Rochu D, Crespeau H, Fine J M
Laboratoire d'Immunochimie Analytique, Institut National de Transfusion Sanguine, Paris.
Rev Fr Transfus Hemobiol. 1991 Jan;34(1):35-47. doi: 10.1016/s1140-4639(05)80087-5.
Normal human serum albumin and bisalbuminic fractions from genetic variants of european origin have been studied by ultrathin-layer isoelectric focusing performed on whole sera or after purification of albumin fractions by affinity chromatography on Blue-Trisacryl. Narrow range ampholytes giving pH gradient between 5 and 8, together with the use of 8 M urea, provided suitable patterns allowing to discriminate the various allotypes. In these conditions, both normal albumin and heterozygous variants were microheterogeneous with several main bands; in the case of normal albumin, four major bands were found, while variants exhibited additional bands differing in number and pI. The position of additional bands comparatively to that of normal albumin was consistent with the electrophoretic behavior of variants. Fast moving allotypes exhibited additional bands with more anodal pIs, whereas slow moving variants were characterized by cathodal additional bands. The number and position of these bands allowed to characterize some variants, when they failed to distinguish between some others, identical patterns being correlated to identical mutations arising at different locations on the albumin molecule. These observations indicate that isoelectric focusing could allow a clear distinction of albumin variants, provided that their mutation were different, or could confirm the occurrence of identical mutation when IEF patterns are indistinguishable. In addition to electrophoretic mobilities at various pH, analytical isoelectric focusing could be a useful technique employed as a second step in the identification of allotypes prior to the determination of the structural change characterizing the variant.
通过对全血清或经 Blue-Trisacryl 亲和层析纯化白蛋白组分后进行超薄层等电聚焦，研究了正常人类血清白蛋白和欧洲起源遗传变异体的双白蛋白组分。使用能产生 5 至 8 pH 梯度的窄范围两性电解质，并结合使用 8 M 尿素，可提供合适的图谱，从而区分各种同种异型。在这些条件下，正常白蛋白和杂合变异体均呈现微异质性，有几条主要条带；对于正常白蛋白，发现了四条主要条带，而变异体则表现出数量和等电点不同的额外条带。与正常白蛋白相比，额外条带的位置与变异体的电泳行为一致。快速移动的同种异型表现出等电点更偏阳极的额外条带，而缓慢移动的变异体则以阴极额外条带为特征。当这些条带的数量和位置无法区分某些变异体时，它们可用于表征一些变异体，相同的图谱与白蛋白分子不同位置发生的相同突变相关。这些观察结果表明，等电聚焦能够清晰区分白蛋白变异体，前提是它们的突变不同，或者当等电聚焦图谱无法区分时，能够确认相同突变的存在。除了在不同 pH 下的电泳迁移率外，分析性等电聚焦可作为在确定表征变异体的结构变化之前鉴定同种异型的第二步的有用技术。
