Activated Factor IX (FIXa)

Activated factor IX (factor IXa) is a serine protease enzyme that plays a central role in the blood coagulation cascade. It is the active form of coagulation factor IX, which circulates in plasma as an inactive zymogen until activated. FIXa forms a complex with calcium ions, membrane phospholipids, and activated cofactor VIIIa to efficiently catalyze conversion of inactive factor X to its active form Xa. Deficiency or dysfunction leads to hemophilia B.

Other names

Factor IXaChristmas Factor, activatedF9a

Catalyzes conversion of inactive factor X to its active form Xa within the intrinsic tenase complex, leading to thrombin generation and fibrin clot formation.