總結(jié) |
This gene encodes coagulation factor XIII B subunit.Coagulation factor XIII is the last zymogen to become activated inthe blood coagulation cascade. Plasma factor XIII is aheterotetramer composed of 2 A subunits and 2 B subunits. The Asubunits have catalytic function, and the B subunits do not haveenzymatic activity and may serve as a plasma carrier molecules.Platelet factor XIII is comprised only of 2 A subunits, which areidentical to those of plasma origin. Upon activation by thecleavage of the activation peptide by thrombin and in the presenceof calcium ion, the plasma factor XIII dissociates its B subunitsand yields the same active enzyme, factor XIIIa, as platelet factorXIII. This enzyme acts as a transglutaminase to catalyze theformation of gamma-glutamyl-epsilon-lysine crosslinking betweenfibrin molecules, thus stabilizing the fibrin clot. Factor XIIIdeficiency is classified into two categories: type I deficiency,characterized by the lack of both the A and B subunits; and type IIdeficiency, characterized by the lack of the A subunit alone.These defects can result in a lifelong bleeding tendency, defectivewound healing, and habitual abortion.
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