Beale D, Coadwell J
Biochim Biophys Acta. 1987 Apr 30;912(3):365-70. doi: 10.1016/0167-4838(87)90041-0.
Tryptic fragments from bovine secretory component and sIgA have been separated by HPLC and/or SDS polyacrylamide gel electrophoresis and electroblotting. Their N-terminal amino acid sequences have been determined and their positions in the secretory component molecule deduced by homology with the amino acid sequences of human secretory component and rabbit polyimmunoglobulin receptor. Taken in conjunction with the known binding affinities of the tryptic fragments, the results imply that the three most N-terminal domains of secretory component are directly involved in binding IgM and IgA dimers. The results also favour the concept of an extended 'zig-zag' structure for the secretory component molecule.
来自牛分泌成分和分泌型免疫球蛋白A（sIgA）的胰蛋白酶消化片段已通过高效液相色谱法（HPLC）和/或十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-聚丙烯酰胺凝胶电泳）及电转印法进行了分离。已确定了它们的N端氨基酸序列，并通过与人分泌成分和兔多聚免疫球蛋白受体的氨基酸序列进行同源性比较，推断出它们在分泌成分分子中的位置。结合胰蛋白酶消化片段已知的结合亲和力，这些结果表明分泌成分最N端的三个结构域直接参与结合IgM和IgA二聚体。这些结果也支持分泌成分分子具有延伸的“之字形”结构这一概念。
