Effect of GFD and ATF on binding of WT-scuPA to suPAR measured as surface plasmon resonance. Binding of scuPA to suPAR was measured using a BIA X optical Biosensor (Biacore). WT-suPAR was coupled to a CM5-research grade sensor chip. (A) Buffer was injected for 3 minutes (no wash) followed by a 3-minute injection of 2 nM scuPA with a 3-minute wash delay (black); 400 nM GFD was injected for 3 minutes (no wash) followed by a mixture of 400 nM GFD plus 2 nM scuPA for 3 minutes with a 3-minute wash delay (gray). (B) Buffer was injected for 3 minutes (no wash) followed by an injection of 2 nM scuPA for 3 minutes with a 3-minute wash delay (black); 400 nM ATF was then injected for 3 minutes (no wash) followed by a mixture of 400 nM ATF plus 2 nM scuPA for 3 minutes with a 3-minute wash delay (gray). Mixtures of scuPA with GFD or ATF were incubated for 30 minutes prior to injection. Data were collected at a flow rate of 30 μL/min with the data collection rate set to “high” (5 data points per second).