Most molecules in the coagulation cascade are bound to phosopholipid on cell membranes, by a Ca2+ bridge, in the active form. This includes extrinsic tenase (VIIa), intrinsic tenase (IXa), and prothrombinase (Xa). What factor is free floating (not bound to PL) in the active form? Why is this dangerous?
Thrombin (factor IIa); It can travel through the blood vessel and form clots (by converting fibrinogen to fibrin) in a region of blood vessel that is not injured. Anticoagulatants are present in the blood to prevent this.