GU81 inhibits VEGF-induced activation of VEGFR2. A) Dimeric structure of the peptoid GU81 B) Biotin-conjugated GU40C4 binds to both VEGFR1 and VEGFR2 as measured by ELISA. GU81 competes with biotinylated GU40C4 for binding to both receptors. C) Fluorescein-conjugated GU81 was titrated and analyzed for binding to VEGFR2 as measured by ELISA. KD= 12 nM. D) Serum starved PAE/KDR cells were stimulated for 7 min with VEGF (1.3 nM) in the presence and absence of the indicated concentration of GU81. Avastin, a blocking anti-VEGF antibody was used as a positive control for inhibition. Cell lysates were made and separated by SDS-PAGE, transferred to PVDF membranes and probed for phosphorylated VEGFR2 and total VEGFR2 by Western blotting. E) Quantification and analysis of the results presented in (D). IC50= 430 nM.