Mescher M F, Pollock R R
J Immunol. 1979 Sep;123(3):1155-61.
The heavy chain of isolated murine cell surface IgD is present in two forms, separable by electrophoresis on SDS-polyacrylamide gradient gels. Both forms of delta-heavy chain are present on the surface of intact spleen cells and have apparent m.w. of approximately 70,000 (delta1) and 68,000 (delta2). Treatment of surface IgD with neuraminidase before isolation results in a single IgD heavy chain band on SDS gels having an apparent m.w. of 65,000, indicating that delta 1 and delta 2 differ in sialic acid content. Delta 2 is removed from the cell surface by papain more readily than delta 1, suggesting a possible functional significance for the two forms.
分离出的鼠细胞表面IgD重链有两种形式，可通过在SDS-聚丙烯酰胺梯度凝胶上进行电泳分离。完整脾细胞表面存在两种形式的δ重链，其表观分子量分别约为70,000（δ1）和68,000（δ2）。在分离前用神经氨酸酶处理表面IgD，SDS凝胶上会出现一条表观分子量为65,000的单一IgD重链带，这表明δ1和δ2在唾液酸含量上存在差异。与δ1相比，木瓜蛋白酶更容易从细胞表面去除δ2，这表明这两种形式可能具有功能上的意义。
