eight day ( 8-d cef ) and 16 day old chick embryo fibroblasts ( 16-d cef ) obtained after a mild trypsin treatment ( 50 micrograms/ml in ca2+ and mg2+-free pbs , plus 10 mm edta ) for 10 min at 37 degrees c present the same number of fibronectin ( fn ) binding sites at their surface ( approximately 550,000 sites per cell ) with a kd approximately equal to 1.40 microm in both cases .
C0016030
fibroblasts
C0007634
cell