Binding of TF to cell-associated TF. CHO cells expressing TF and wild-type cells (4 × 10⁴) was incubated with 50 nmol/L ¹²⁵I-plasminogen in the presence or absence of 100 mmol/L 6-AHA for 2 hours at 37°C. The cells were washed three times in PBS, the cell-associated radioactivity was measured, and the specific binding was calculated. The mean ± SEM of three experiments is shown.