Prothrombin is the Thrombin precursor.
The conversion of prothrombin to the active enzyme thrombin is crucial for proper clot formation.
This conversion is handled by the membrane-bound prothrombinase complex, which contains a protease that sequentially cleaves the prothrombin precursor at Arg320 followed by Arg271. This defined chain of events is believed to occur through exosite-dependent binding of prothrombin to prothrombinase, arranging the substrate so to precisely present Arg320 in the protease active site.
