== Factor Xa ==
[[Ficheiro:Coagulation in vivo-
Factor Xa is the activated form of the [[coagulation factor]] [[thrombokinase]], known eponymously as Stuart-Prower factor. Factor X is an [[enzyme]], a [[serine endopeptidase]], which plays a key role at several stages of the [[coagulation system]]. Factor X is [[Biosynthesis|synthesized]] in the [[liver]]. The most commonly used [[anticoagulants]] in clinical practice, [[warfarin]] and the [[heparin]] series of anticoagulants and [[fondaparinux]], act to inhibit the action of Factor Xa in various degrees.