Teng M H, Rifkin D B
J Cell Biol. 1979 Mar;80(3):784-91. doi: 10.1083/jcb.80.3.784.
Fibronectin isolated from cultures of chicken embryo fibroblasts (CEF) contains phosphorus linked to serine and threonine by monoester bonds. Normal and Rous sarcoma virus (RSV)-transformed cells were incubated with [32P]orthophosphate, and fibronectin was isolated from the cell surfaces and conditioned media. 32P was stably associated with fibronectin during immunoprecipitation, SDS-polyacrylamide gel electrophoresis, phospholipid solvent extraction, and hot acid but not alkaline treatment. After a limited acid hydrolysis of fibronectin, both phosphoserine and phosphothreonine were found. The specific radioactivity of the 32P-labeled fibronectin from the conditioned medium of normal CEF was higher than that from the cultures of transformed CEF.
从鸡胚成纤维细胞（CEF）培养物中分离出的纤连蛋白含有通过单酯键与丝氨酸和苏氨酸相连的磷。将正常细胞和劳氏肉瘤病毒（RSV）转化的细胞与[32P]正磷酸盐一起孵育，然后从细胞表面和条件培养基中分离出纤连蛋白。在免疫沉淀、SDS-聚丙烯酰胺凝胶电泳、磷脂溶剂萃取以及热酸处理而非碱处理过程中，32P与纤连蛋白稳定结合。对纤连蛋白进行有限的酸水解后，发现了磷酸丝氨酸和磷酸苏氨酸。正常CEF条件培养基中32P标记的纤连蛋白的比放射性高于转化CEF培养物中的比放射性。
