Panel 6 (ASH)

6. Kinetics of protease inhibition by antithrombin
Time courses of inhibition of thrombin or factor Xa by antithrombin were determined under pseudo-first-order conditions (i.e., with a molar excess of antithrombin) in the absence of heparin. The monoclonal IgG increased the rate constant for thrombin inhibition 2.7-fold but did not affect the rate constant for factor Xa inhibition.

-IgG +IgG

Thrombin 2.2 x 10⁵ M^-1min^-1 5.9 x 10⁵ M^-1min^-1

Factor Xa 5.3 x 10⁴ M^-1min^-1 5.3 x 10⁴ M^-1min^-1

Control experiments showed that polyclonal human IgG had no effect on the rate of inhibition of thrombin by antithrombin.

title | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11

	-IgG	+IgG
Thrombin	2.2 x 10⁵ M^-1min^-1	5.9 x 10⁵ M^-1min^-1
Factor Xa	5.3 x 10⁴ M^-1min^-1	5.3 x 10⁴ M^-1min^-1