Function
Factor XII is part of the coagulation cascade and activates factor XI and prekallikrein. Factor XII itself is activated to factor XIIa by negatively charged surfaces, such as glass.
In vivo, factor XII is activated by contact to polyanions. Activated platelets secrete inorganic polymers, polyphosphates. Contact to polyphosphates activates factor XII and initiates fibrin formation by the intrinsic pathway of coagulation with critical importance for thrombus formation.Targeting polyphosphates with phosphatases interfered with procoagulant activity of activated platelets and blocked platelet-induced thrombosis in mice. Addition of polyphosphates restored defective plasma clotting of Hermansky-Pudlak syndrome patients, indicating that the inorganic polymer is the endogenous factor XII activator in vivo. Platelet polyphosphate-driven factor XII activation provides the link from primary hemostasis (formation of a platelet plug) with secondary hemostasis (fibrin meshwork formation).
Read more about this topic: Factor XII
Famous quotes containing the word function:
“Science has fulfilled her function when she has ascertained and enunciated truth.”
—Thomas Henry Huxley (1825–95)
“Nobody seriously questions the principle that it is the function of mass culture to maintain public morale, and certainly nobody in the mass audience objects to having his morale maintained.”
—Robert Warshow (1917–1955)
“The art of living is to function in society without doing violence to one’s own needs or to the needs of others. The art of mothering is to teach the art of living to children.”
—Elaine Heffner (20th century)