An Automated Approachto Characterize, in Simple KineticTerms, the Generation and Inactivationof Thrombin and the Interactionof Fibnnogenwith Thrombin

Here, we used a fully automated, computer-directed centrifUgal analyzer (which permitted simultaneous turbidimetry and calculation of results) and purifed thrombin, fibrinogen, and various inhibitors to study clot formation. The l and Vmfor these reactionswere useful in detecting and partlycharacterizing anticoagulants. We also explored the generation and inactivation of thrombin, using the two-stage prothrombin time and antithrombin activity tests. The amount of thrombin instantaneously generated and inactivated was monitored under artificially created pathological conditions. The pseudo-first-order rate constant for thrombin generation and inactivation and the instantaneous concentration of enzymatically active and inactive thrombin were used in the characterization of these conditions. We believe this approach is suitable for routine clinical use.