Beppu M, Masa H, Kikugawa K
Tokyo College of Pharmacy, Japan.
FEBS Lett. 1989 Jan 2;242(2):378-82. doi: 10.1016/0014-5793(89)80505-8.
Fibronectin (FN) was detected on thioglycollate-induced mouse peritoneal macrophages by binding the 125I-labeled F(ab')2 fragment of rabbit anti-human plasma fibronectin. The cell surface fibronectin (sFN) was removed from the surface of the macrophage monolayer by limited trypsinization. After trypsinization, binding of 125I-labeled plasma fibronectin (125I-pFN) to the macrophage monolayer was increased, suggesting that the FN receptor covered with sFN was exposed by trypsinization without destroying the receptor activity. The amounts of saturation binding of 125I-pFN to the macrophage monolayers before and after trypsinization were about 2.4 and 6.3 micrograms per 10(6) cells, respectively, indicating that the macrophage monolayer has the capacity of binding 6.3 micrograms FN per 10(6) cells, and the FN receptor equivalent to about 4 micrograms pFN per 10(6) cells is covered with sFN.
通过结合兔抗人血浆纤连蛋白的125I标记F(ab')2片段，在巯基乙酸盐诱导的小鼠腹腔巨噬细胞上检测到纤连蛋白（FN）。通过有限的胰蛋白酶消化从巨噬细胞单层表面去除细胞表面纤连蛋白（sFN）。胰蛋白酶消化后，125I标记的血浆纤连蛋白（125I-pFN）与巨噬细胞单层的结合增加，这表明被sFN覆盖的FN受体通过胰蛋白酶消化暴露出来，而没有破坏受体活性。胰蛋白酶消化前后125I-pFN与巨噬细胞单层的饱和结合量分别约为每10(6)个细胞2.4微克和6.3微克，这表明巨噬细胞单层具有每10(6)个细胞结合6.3微克FN的能力，并且每10(6)个细胞中约相当于4微克pFN的FN受体被sFN覆盖。
