Mullock B M, Dobrota M, Hinton R H
Biochim Biophys Acta. 1978 Nov 1;543(4):497-507. doi: 10.1016/0304-4165(78)90304-5.
The protein composition of rat bile has been studied systematically using two-dimensional agarose-polyacrylamide gel electrophoresis, with or without prior absorption by immobilised antisera, and by crossed immunoelectrophoresis. Sixteen bile proteins were distinguished. Of these, thirteen are immunologically identical to proteins present in rat serum and only one is identical to a protein present in rat liver plasma membrane but not in rat serum. Of the remaining two proteins, one is bile lipoprotein and the other has many of the properties of immunoglobulin A secretory component. The serum-related proteins in rat bile fall into two distinct groups. In the first group are immunoglobulin A and an alpha2-globulin. These proteins are major constituents of bile but only minor constituents of serum. In the second group are albumin and some other major serum proteins which are found in bile at concentrations less than 1% of their concentrations in serum. The relative proportions of these proteins in bile appear to differ from their proportions in serum. It therefore appears that, although the majority of bile proteins are derived from serum, there cannot be direct leakage of serum into bile. Examination of the proteins contained within liver lysosomes indicates that, although discharge of lysosomal contents at the bile canalicular face of the hepatocyte may contribute to the bile proteins, an additional mechanism, with a considerable degree of selectivity, must also be involved in the transport of proteins from serum to bile.
运用二维琼脂糖-聚丙烯酰胺凝胶电泳法，结合或不结合固定化抗血清预先吸收处理，以及交叉免疫电泳法，对大鼠胆汁的蛋白质组成进行了系统研究。共鉴别出16种胆汁蛋白。其中，13种在免疫上与大鼠血清中的蛋白质相同，只有1种与大鼠肝细胞膜而非大鼠血清中存在的一种蛋白质相同。其余两种蛋白质中，一种是胆汁脂蛋白，另一种具有许多免疫球蛋白A分泌成分的特性。大鼠胆汁中与血清相关的蛋白质分为两个不同的组。第一组是免疫球蛋白A和一种α2球蛋白。这些蛋白质是胆汁的主要成分，但只是血清的次要成分。第二组是白蛋白和其他一些主要的血清蛋白，它们在胆汁中的浓度低于其在血清中浓度的1%。这些蛋白质在胆汁中的相对比例似乎与其在血清中的比例不同。因此，尽管大多数胆汁蛋白来源于血清，但血清不可能直接渗漏到胆汁中。对肝溶酶体中所含蛋白质的检查表明，尽管肝细胞胆小管面溶酶体内容物的排出可能对胆汁蛋白有贡献，但从血清到胆汁的蛋白质转运必定还涉及一种具有相当程度选择性的额外机制。
