Transglutaminase in blood coagulation: Factor XIIIa (FXIIIa): Crosslinking of fibrin скачать в хорошем качестве

Transglutaminase in blood coagulation: Factor XIIIa (FXIIIa): Crosslinking of fibrin

http://webs.ono.com/fotgcren/index.htm Compilation of videos showing the role of the transglutaminase present in blood which is called FACTOR XIIIa or FXIIIa. The coagulation cascade has evolved as an essential defense mechanism for maintaining hemostasis during tissue or blood vessel injury (Nikolajsen 2014) Activation of the cascade ultimately results in the formation of an insoluble blood clot (Nikolajsen 2014). The clot consists mainly of fibrin fibers, platelets and red blood cells (Nikolajsen 2014). The fibers are formed when activated thrombin cleaves fibrinogen into fibrin monomers, which then assemble into fibrin fibers (Nikolajsen 2014). To obtain fibers that are capable of resisting mechanical shear and proteolytic degradation, concurrent cleavage of coagulation factor XIII (FXIII) by thrombin is needed (Nikolajsen 2014). Once cleaved and activated, FXIIIa is able to stabilize the fibrin fibers and alter the characteristics of the clot (Nikolajsen 2014). Although activation of the coagulation cascade and consequently FXIIIa is essential during blood vessel damage, it may contribute negatively in pathological situations such as sepsis and cardiovascular disease (Nikolajsen 2014). FXIIIa belongs to the family of human transglutaminases (TG) (E.C 2.3.2.13) (Nikolajsen 2014). This group of enzymes is defined by their common ability to catalyze thiol- and Ca2+- dependent transamidation reactions (Nikolajsen 2014). The TG-catalyzed reaction between specific Gln and Lys residues within substrate proteins results in the formation of covalent cross-links, defined as ε-(γ-glutamyl)lysine isopeptide bonds (Nikolajsen 2014). The major physiological function of FXIIIa is to stabilize the fibrin clot during coagulation (Nikolajsen 2014). FXIIIa cross-links α- and γ-chains of fibrin monomers within fibrin fibers once these have been formed (Nikolajsen 2014). The inter-molecular cross-linking of the fibrin monomers converts loose fibrin fibers into a stable fiber network that is able to withstand mechanical stress and resist clot rupture (Nikolajsen 2014). FXIIIa deficiency, which causes severe bleeding diathesis, demonstrates the essential role of FXIIIa in coagulation (Nikolajsen 2014). Copyright Disclaimer Under Section 107 of the Copyright Act 1976, allowance is made for "fair use" for purposes such as criticism, comment, news reporting, teaching, scholarship, and research. Fair use is a use permitted by copyright statute that might otherwise be infringing. Non-profit, educational or personal use tips the balance in favor of fair use