Borke J L, Caride A, Verma A K, Penniston J T, Kumar R
Department of Medicine, Mayo Clinic and Foundation, Rochester, MN 55905.
Pflugers Arch. 1990 Sep;417(1):120-2. doi: 10.1007/BF00370781.
We used a monoclonal antibody (5F10) specific for the human erythrocyte plasma membrane Ca(++)-pump to demonstrate the presence and distribution of Ca(++)-pump epitopes in rat intestine. In paraffin embedded tissue sections, antibody 5F10 binds to epitopes in the basolateral membranes of absorptive cells in rat duodenum and portions of jejunum but not ileum. Western blot analysis of intestinal mucosal proteins with antibody 5F10 shows binding of antibody to major bands of Mr approximately 135,000 and Mr approximately 72,000, and to lesser bands of Mr approximately 125,000 and Mr approximately 27,000. This pattern was seen in mucosal homogenates of rat duodenal and jejunal cells and to a lesser extent in ileal cells. The Mr approximately 135,000 band corresponds to the molecular weight of Ca(++)-pumps in other tissues. The other bands correspond in size to known proteolytic fragments of the Ca(++)-pump. Slot-blot analysis of nitrocellulose immobilized mucosal homogenates shows binding of 5F10 to be greatest in duodenum and least in ileum. Ca(++)-transport studies by the everted gut sac technique show a correlation between vitamin D induction of active Ca(++)-transport and the segmental distribution of Ca(++)-pump epitopes.
我们使用了一种对人红细胞质膜Ca(++)泵具有特异性的单克隆抗体（5F10），以证明Ca(++)泵表位在大鼠肠道中的存在和分布。在石蜡包埋的组织切片中，抗体5F10与大鼠十二指肠和部分空肠吸收细胞的基底外侧膜中的表位结合，但不与回肠结合。用抗体5F10对肠粘膜蛋白进行的蛋白质印迹分析显示，抗体与分子量约为135,000和分子量约为72,000的主要条带结合，并与分子量约为125,000和分子量约为27,000的较小条带结合。这种模式在大鼠十二指肠和空肠细胞的粘膜匀浆中可见，在回肠细胞中程度较轻。分子量约为135,000的条带对应于其他组织中Ca(++)泵的分子量。其他条带的大小与Ca(++)泵的已知蛋白水解片段相对应。对硝酸纤维素固定的粘膜匀浆进行的狭缝印迹分析显示，5F10的结合在十二指肠中最大，在回肠中最小。通过外翻肠囊技术进行的Ca(++)转运研究表明，维生素D诱导的活性Ca(++)转运与Ca(++)泵表位的节段分布之间存在相关性。
