Fig. 2.
Fig. 2. APC-catalyzed inactivation of platelet-derived factor Va and factor VaLeiden bound to thrombin-activated platelets. Platelets (1 × 109/mL) in the presence of RGDS peptide (1 mmol/L) from normal (A; n = 3) and factor VLeidenindividuals (B; n = 3) were treated with 5 NIH U/mL (50 nmol/L) of α-thrombin for 5 minutes. Hirudin (60 nmol/L) was then added to inhibit thrombin. The resulting thrombin-activated platelets were then used as the required membrane surface for the APC-catalyzed inactivation of platelet-derived factor Va. APC (0.25 nmol/L) was added and residual cofactor activity and proteolytic fragments derived from APC-catalyzed inactivation were monitored as described in Fig 1. The line drawn through the inactivation profiles (A and B) represents the average of the three donors at each given time point and does not represent an attempt to fit the data to a first-order rate equation. The data points were normalized to the initial concentration of released cofactor for each donor. In (A), each of the symbols represents the time-dependent, APC-catalyzed inactivation of the platelet-derived factor Va cofactor activity from three normal donors (initial cofactor concentrations: 1.40, 1.90, and 2.30 nmol/L). The inset represents the proteolytic fragments derived from the inactivation on thrombin-activated platelets. Lane 1, platelet-derived factor Va, no APC; lanes 2 through 9, platelet-bound platelet-derived factor Va with APC for 1, 5, 10, 15, 30, 90, 120, and 180 minutes. In (B), each of the symbols represents the platelet-derived factor VaLeiden cofactor activity from three factor VLeiden donors (initial cofactor concentrations: 0.91, 0.93, and 1.40 nmol/L). The inset represents the proteolytic fragments derived from the inactivation on thrombin-activated platelets. Lane 1, platelet-derived factor VaLeiden, no APC; lanes 2 through 10, platelet-bound platelet-derived factor VaLeiden with APC for, 1, 5, 10, 15, 30, 90, 120, 150, and 180 minutes. The position of the molecular weight markers are indicated at the left of the insets.

APC-catalyzed inactivation of platelet-derived factor Va and factor VaLeiden bound to thrombin-activated platelets. Platelets (1 × 109/mL) in the presence of RGDS peptide (1 mmol/L) from normal (A; n = 3) and factor VLeidenindividuals (B; n = 3) were treated with 5 NIH U/mL (50 nmol/L) of α-thrombin for 5 minutes. Hirudin (60 nmol/L) was then added to inhibit thrombin. The resulting thrombin-activated platelets were then used as the required membrane surface for the APC-catalyzed inactivation of platelet-derived factor Va. APC (0.25 nmol/L) was added and residual cofactor activity and proteolytic fragments derived from APC-catalyzed inactivation were monitored as described in Fig 1. The line drawn through the inactivation profiles (A and B) represents the average of the three donors at each given time point and does not represent an attempt to fit the data to a first-order rate equation. The data points were normalized to the initial concentration of released cofactor for each donor. In (A), each of the symbols represents the time-dependent, APC-catalyzed inactivation of the platelet-derived factor Va cofactor activity from three normal donors (initial cofactor concentrations: 1.40, 1.90, and 2.30 nmol/L). The inset represents the proteolytic fragments derived from the inactivation on thrombin-activated platelets. Lane 1, platelet-derived factor Va, no APC; lanes 2 through 9, platelet-bound platelet-derived factor Va with APC for 1, 5, 10, 15, 30, 90, 120, and 180 minutes. In (B), each of the symbols represents the platelet-derived factor VaLeiden cofactor activity from three factor VLeiden donors (initial cofactor concentrations: 0.91, 0.93, and 1.40 nmol/L). The inset represents the proteolytic fragments derived from the inactivation on thrombin-activated platelets. Lane 1, platelet-derived factor VaLeiden, no APC; lanes 2 through 10, platelet-bound platelet-derived factor VaLeiden with APC for, 1, 5, 10, 15, 30, 90, 120, 150, and 180 minutes. The position of the molecular weight markers are indicated at the left of the insets.

Close Modal
This Feature Is Available To Subscribers Only

or Create an Account

Close Modal
Close Modal