. 2010 Sep 23;117(1):290–298. doi: 10.1182/blood-2010-08-300756

Table 1.

Inhibition kinetics of FXa or prothrombinase

	Inhibitor
	Antithrombin III, k₂ ± SD × 10³, M⁻¹ s⁻¹	TFPI, K_i*, nM
Free FXa
wt-FXa	1.28 ± 0.060	0.07 ± 0.012
FXa^I16L	0.03 ± 0.006	1.86 ± 0.340
FXa^V17A	0.05 ± 0.002	1.16 ± 0.120
Prothrombinase
wt-FXa	0.18 ± 0.010	ND
FXa^I16L	0.09 ± 0.006	ND
FXa^V17A	0.05 ± 0.003	ND

The errors in the fitted constants represent ± 2 SDs. The data are representative of 2-3 independent measurements. Inhibition kinetics of FXa alone or prothrombinase were determined from initial velocity studies conducted with peptidyl substrate, Spec Xa. Details of the experimental design can be found in “Methods.”

ND, not determined.