Table 1.

Specificity of Ixolaris to FVIIa/TF-induced FX activation

Enzymes/substratesResidual activity (%)
VIIa/TF (6.4 pM)/S2288 (1 mM) 0  
Thrombin (125 pM)/S2238 (250 μM) 103 ± 1.56  
Chymotrypsin (22.4 nM)/S2222 (250 μM) 101.5 ± 0.09  
FXIa (58.7 pM)/S2256 (250 μM) 89.2 ± 3.1  
Reptilase (0.3125 BU/mL)/S2238 (250 μM) 98.5 ± 0.52  
Plasmin (5 mU/mL)/S2251 (250 μM) 107.5 ± 0.75  
Elastase (250 pM)/substrate (500 μM) 106 ± 8.02  
Tryptase (0.4 μg/mL)/S2222 (250 μM) 101 ± 0.07 
Enzymes/substratesResidual activity (%)
VIIa/TF (6.4 pM)/S2288 (1 mM) 0  
Thrombin (125 pM)/S2238 (250 μM) 103 ± 1.56  
Chymotrypsin (22.4 nM)/S2222 (250 μM) 101.5 ± 0.09  
FXIa (58.7 pM)/S2256 (250 μM) 89.2 ± 3.1  
Reptilase (0.3125 BU/mL)/S2238 (250 μM) 98.5 ± 0.52  
Plasmin (5 mU/mL)/S2251 (250 μM) 107.5 ± 0.75  
Elastase (250 pM)/substrate (500 μM) 106 ± 8.02  
Tryptase (0.4 μg/mL)/S2222 (250 μM) 101 ± 0.07 

Ixolaris (32 nM, final concentration) was preincubated for 15 minutes at 37°C with the enzymes listed, followed by addition of the appropriate chromogenic substrate. Reactions were followed for 30 minutes at 37°C, and the effect of Ixolaris was estimated by setting the initial velocity obtained in the presence of enzyme alone (without inhibitor) as 100%.