Competitive inhibition of FXIII-A₂B₂ binding to GSTα fragment 1 and fibrin with the use of α fragment 9 (α371-425). PreScission-cleaved α fragment 9 was preincubated, at increasing molar concentrations (0μM, 0.012μM, 0.125μM, 1.25μM, and 12.5μM where 0μM refers to activated FXIII-A₂B₂ in the absence of any α fragment 9 competitor) for 60 seconds with 125nM thrombin-activated FXIII-A₂B₂ in the presence of calcium. The sample was injected for 60 seconds at a flow rate of 30 μL/min over captured GSTα fragment 1 and immobilized fibrin. The binding response (RU) was converted to the percentage of binding of FXIII-A₂B₂ to captured GSTα fragment 1 (■) or immobilized fibrin (♦). Results are normalized to binding in the absence of the competitor (n = 3).