Tomiyama Y, Kurata Y, Shibata Y, Take H, Furubayashi T, Tsubakio T, Yonezawa T, Tarui S
Nihon Ketsueki Gakkai Zasshi. 1989 Aug;52(5):887-94.
We investigated the location of platelet-specific alloantigen Baka on platelet membrane glycoproteins. In indirect immunoprecipitation experiments, the anti-Baka antibody precipitated glycoprotein (GP) II b and a small amount of GP III a. The immunoblots using partially purified GP II b/III a complex as the target antigen indicated that GP II b alpha carried the Baka alloantigen. When the partially purified GP II b/III a complex digested with chymotrypsin was examined, the Baka alloantigen was found on a 65 kD fragment derived from GP II b alpha under reducing conditions. In addition, the immunoblots after two-dimensional nonreduced-reduced SDS-PAGE directly indicated that the 65 kD fragment had a mol. wt. of 80 kD under nonreducing conditions. The immunoblots using platelets digested in situ with chymotrypsin indicated that the 65 kD fragment of GP II b alpha was retained by the platelet membrane. We conclude, therefore, that the Baka alloantigen is located on a 65 kD fragment that represents the membrane side of the cleavage site of chymotrypsin on GP II b alpha.
我们研究了血小板特异性同种抗原Baka在血小板膜糖蛋白上的定位。在间接免疫沉淀实验中，抗Baka抗体沉淀出糖蛋白（GP）IIb和少量的GP IIIa。以部分纯化的GP IIb/IIIa复合物作为靶抗原的免疫印迹表明，GP IIbα携带Baka同种抗原。当检测用胰凝乳蛋白酶消化的部分纯化的GP IIb/IIIa复合物时，在还原条件下，Baka同种抗原存在于源自GP IIbα的65kD片段上。此外，二维非还原-还原SDS-PAGE后的免疫印迹直接表明，在非还原条件下，该65kD片段的分子量为80kD。用胰凝乳蛋白酶原位消化血小板后的免疫印迹表明，GP IIbα的65kD片段被血小板膜保留。因此，我们得出结论，Baka同种抗原位于一个65kD片段上，该片段代表胰凝乳蛋白酶在GP IIbα上切割位点的膜侧。
