Line graph showing the binding of increasing amounts of iodinated recombinant full-length TFPI (TFPI) and C-terminal truncated TFPI (TFPI_1-161 ) to HUVEC after incubation for 2 hours at 4°C (upper panel). Addition of increasing amounts of unlabeled TFPI simultanously with 0.5 nmol/L ¹²⁵I-TFPI was conducted to see if unlabeled TFPI would inhibit an interaction between ¹²⁵I-TFPI and a specific receptor (lower panel). Each symbol represents the mean of triplicate determinations.