Chan V, Chan T K
Thromb Haemost. 1982 Oct 29;48(2):177-81.
Crossed immunoelectrophoresis showed that factor VIII related protein (VIII R) synthesized in the human endothelial cell (EC-VIII R) had faster electrophoretic mobility than that secreted into the culture medium (MED-VIII R). Sodium dodecyl sulphate agarose gel electrophoresis followed by radioimmunofixation showed that EC-VIII R consisted of molecules varying from 0.26 x 10(6) to 3.76 x 10(6) daltons while MED-VIII R had molecules ranging from 0.93 x 10(6) to greater than 10 x (10)6 daltons, similar to that present in plasma. The smallest VIII R molecule present in normal plasma or spent culture medium (0.93 x 10(6) daltons) corresponded to a tetramer of subunits of 0.22-0.24 x 10(6) daltons. Only molecular forms greater than 3.76 x 10(6) daltons possessed ristocetin cofactor activity. Sonication (15 mu amplitude for 30 secs) effectively broke the non-covalent bonds of the VIII R multimers resulting in smaller molecules. Thus endothelial cells in culture synthesized VIII R subunits and assembled them into the higher multimeric forms on secretion. Different types of von Willebrand disease could result from defects of either of the two processes.
交叉免疫电泳显示，人内皮细胞合成的因子VIII相关蛋白（VIII R，即EC-VIII R）的电泳迁移率比分泌到培养基中的因子VIII相关蛋白（MED-VIII R）更快。十二烷基硫酸钠琼脂糖凝胶电泳后进行放射免疫固定显示，EC-VIII R由分子量从0.26×10⁶到3.76×10⁶道尔顿不等的分子组成，而MED-VIII R的分子分子量范围为0.93×10⁶到大于10×10⁶道尔顿，与血浆中的情况相似。正常血浆或用过的培养基中存在的最小VIII R分子（0.93×10⁶道尔顿）相当于分子量为0.22 - 0.24×10⁶道尔顿的亚基四聚体。只有分子量大于3.76×10⁶道尔顿的分子形式具有瑞斯托霉素辅因子活性。超声处理（振幅15微米，持续30秒）有效地破坏了VIII R多聚体的非共价键，产生了较小的分子。因此，培养中的内皮细胞合成VIII R亚基，并在分泌时将它们组装成更高的多聚体形式。不同类型的血管性血友病可能由这两个过程中任何一个的缺陷导致。
