- Human pathology

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Saturday 4 February 2006

Factor XIII is a proenzyme for fibrinoligase and is converted into the active form under the influence of thrombin (MIM.176930) and calcium ion.

Factor XIII is the last enzyme generated in the blood coagulation cascade. It is the zymogen for fibrinoligase, a transglutaminase, which forms intramolecular gamma-glutamyl-epsilon-lysine crosslinking between fibrin molecules. Crosslinking of fibrin stabilizes clot.

Factor XIII is composed of 2 A subunits F13A (MIM.134570), which have catalytic function, and 2 B subunits F13B (MIM.134580). The F13B subunits of factor XIII apparently have no enzymatic activity and may serve as plasma carrier molecules.


F13A F13B


- F13B deficiency

  • complete absence of the B subunit of factor XIII