Calculation of second-order rate constants. Thrombin (10 nM) and inhibitor (AT, 0.3 μM; A1PI, 135 μM; HCII, 1.2 μM; and A2M, 2.4 μM) were incubated. At time points, residual thrombin was measured by addition of a chromogenic thrombin substrate. Note that each plot has a separate time course. The rate of thrombin inhibition was calculated from an exponential decay curve fit to the data (equation 1). As expected, the A2M/IIa complex retains some ability to cleave substrate (equation 2). The shaded area indicates the 95% confidence interval of the fit to the data. The rate measured from each curve fit was divided by the concentration of inhibitor to give the second-order rate constant shown in Table 1. Also shown in Table 1 is the plasma concentration of each inhibitor.
Figure 1.

Calculation of second-order rate constants. Thrombin (10 nM) and inhibitor (AT, 0.3 μM; A1PI, 135 μM; HCII, 1.2 μM; and A2M, 2.4 μM) were incubated. At time points, residual thrombin was measured by addition of a chromogenic thrombin substrate. Note that each plot has a separate time course. The rate of thrombin inhibition was calculated from an exponential decay curve fit to the data (equation 1). As expected, the A2M/IIa complex retains some ability to cleave substrate (equation 2). The shaded area indicates the 95% confidence interval of the fit to the data. The rate measured from each curve fit was divided by the concentration of inhibitor to give the second-order rate constant shown in Table 1. Also shown in Table 1 is the plasma concentration of each inhibitor.

This Feature Is Available To Subscribers Only

or Create an Account

Close Modal
Close Modal