Binding of intact/nicked β2GPI to AS4.5. (A) Kinetic curves showing molecular interaction between AS4.5 and intact or nicked β2GPI. Intact β2GPI or nicked β2GPI binding to immobilized AS4.5 was detected using Biacore X, an optical biosensor as described in “Kinetic assay for molecular interaction between nicked B2GPI and AS4.5.” Binding curve was compared between intact (left panel) and nicked β2GPI (right panel). Binding constants (K_D and K_A) between AS4.5 and nicked β2GPI were determined. (B) Binding of nicked β2GPI to immobilized Glu-plasminogen was tested in the presence or absence of AS4.5 in the fluid, using ELISA. The abilities of AS4.5 to inhibit the binding between fluid-phase nicked β2GPI and solid-phase Glu-plasminogen were shown as percentage inhibition. Error bars represent SE.