Fig. (8) Effect of reactant concentrations of thrombin and heparin in the reaction of Serp-1 and thrombin. 10 µL samples were incubated at room temperature for 20 minutes, followed by adding the SDS-PAGE loading buffer, electrophoresis on a 12% gel, and staining with Coomassie blue kit (Gel-Code Blue, Pierce). Lanes 1 to 8 contained 1 μg Serp-1. Lanes 1 and 9 contained 2 NIH units throm-bin; lane 2, 1 NIH unit thrombin; lane 3, 0.5 NIH units thrombin; lane 4, 0.25 NIH units thrombin; lane 5, 0.12 NIH units thrombin; lane 6, 0.06 NIH units thrombin; lane 7, 0.03 NIH units thrombin. (A) There was no heparin added into the reaction. Heparin at 0.001 IU (B) and 0.01 IU (C) was added prior to the thrombin reaction. S lane contained molecular markers (kDa). Arrows at left indicate the complex band (top) and cleaved Serp-1 band (bottom). Arrowheads at right indicate the native Serp-1 and thrombin bands, respectively.