Yamada M, Okigaki T, Awai M
Eur J Cell Biol. 1987 Apr;43(2):230-4.
In the present study we show that adhesion of normal rat liver epithelial cells (RL34) to substratum coated with type I collagen (collagen substratum) is promoted by a factor involved in 80% ammonium sulfate precipitated proteins from serum-free conditioned medium (PCM) of rat embryo fibroblasts. Adhesion of RL34 cells to collagen substratum was promoted dose dependently by whole PCM and the maximum effects on adhesion could be achieved by 200 micrograms/ml whole PCM. Kinetics studies with 100 micrograms/ml whole PCM showed that adhesion proceeded very slowly, taking 16 h to reach a plateau. Adhesion-promoting activity in whole PCM was sensitive to treatments with trypsin, acid, and heat but stable to dithiothreitol treatment. Further purification of whole PCM was performed using a combination of chromatography on blue Sepharose column, gel filtration column and heparin Sepharose column. The partially purified proteins, referred to as heparin PCM, are not bound or only weakly bound to heparin under physiological ion strength and pH, and the apparent molecular weight (Mr) range is estimated to be 40,000 to 60,000 from gel filtration chromatography and SDS-polyacrylamide gel electrophoresis. When whole PCM or heparin PCM was used for coating on plastic or collagen substratum, they no longer exerted the promoting activity.
在本研究中，我们发现正常大鼠肝上皮细胞（RL34）与包被有I型胶原的基质（胶原基质）的黏附，可被一种来自大鼠胚胎成纤维细胞无血清条件培养基（PCM）中80%硫酸铵沉淀蛋白的因子所促进。RL34细胞与胶原基质的黏附受全PCM的剂量依赖性促进，200微克/毫升全PCM可对黏附产生最大效应。用100微克/毫升全PCM进行的动力学研究表明，黏附进展非常缓慢，需16小时才能达到平台期。全PCM中的黏附促进活性对胰蛋白酶、酸和加热处理敏感，但对二硫苏糖醇处理稳定。使用蓝琼脂糖柱、凝胶过滤柱和肝素琼脂糖柱色谱相结合的方法对全PCM进行进一步纯化。部分纯化的蛋白质，称为肝素PCM，在生理离子强度和pH条件下不与肝素结合或仅与肝素弱结合，根据凝胶过滤色谱和SDS-聚丙烯酰胺凝胶电泳估计其表观分子量（Mr）范围为40,000至60,000。当将全PCM或肝素PCM用于包被塑料或胶原基质时，它们不再发挥促进活性。
