Binding of VEGF to fibrin monomer.

(A) Fibrinogen was immobilized on Sepharose beads and then converted to fibrin monomer by incubation with thrombin. ¹²⁵I-VEGF was incubated with the beads, and bound and free ligand were then separated by centrifugation. Non-specific binding (squares) was measured in the presence of a 10-fold molar excess of unlabeled VEGF, and specific binding (triangles) was determined by subtraction of non-specific binding from total binding (diamonds). Each point represents the mean ± SD of 3 different experiments. (B) Scatchard plot. The best fit of the data was determined using the Ligand program and indicated the presence of 2 distinct binding sites. (C) Competitive inhibition of binding. Increasing concentrations of unlabeled VEGF were used to competitively inhibit the binding of ¹²⁵I-VEGF to fibrinogen. Each point represents mean ± SD of 3 different experiments.