Sadeghi H, da Silva A M, Klein C
E.A. Doisy Department of Biochemistry, St. Louis University School of Medicine, MO 63104.
Proc Natl Acad Sci U S A. 1988 Aug;85(15):5512-5. doi: 10.1073/pnas.85.15.5512.
We describe the biochemical features of the putative cell cohesion molecule antigen 117, indicating that it is anchored to the plasma membrane by a glycolipid tail. Antigen 117 can be radiolabeled with [3H]myristate, [3H]palmitate, and [14C]ethanolamine. The fatty acid label is removed by periodate oxidation and nitrous acid deamination, indicating that the fatty acid is attached to the protein by a structure containing carbohydrate and an unsubstituted glucosamine. As cells develop aggregation competence, the antigen is released from the cell surface in a soluble form that can still be radiolabeled with [14C]ethanolamine but not with [3H]myristate or [3H]palmitate. The molecular weight of the released antigen is similar to that found in the plasma membrane, but it preferentially partitions in Triton X-114 as a hydrophilic, as opposed to a hydrophobic, protein. Plasma membranes contain the enzyme activity responsible for the release of the antigen in a soluble form.
我们描述了假定的细胞黏附分子抗原117的生化特性，表明它通过糖脂尾巴锚定在质膜上。抗原117可用[3H]肉豆蔻酸、[3H]棕榈酸和[14C]乙醇胺进行放射性标记。脂肪酸标记可通过高碘酸盐氧化和亚硝酸脱氨去除，这表明脂肪酸通过含有碳水化合物和未取代葡糖胺的结构与蛋白质相连。随着细胞形成聚集能力，该抗原以可溶形式从细胞表面释放，这种可溶形式仍可用[14C]乙醇胺进行放射性标记，但不能用[3H]肉豆蔻酸或[3H]棕榈酸标记。释放的抗原的分子量与质膜中的相似，但它在Triton X-114中优先作为亲水性而非疏水性蛋白质进行分配。质膜含有负责以可溶形式释放抗原的酶活性。
