Factor XIIIa (Last Updated - 2/28/2005)

-formed via activation of Factor XIII --> this reaction is catalyzed by calcium (Factor IV) & Factor IIa (thrombin)
-Factor XIIIa in turn takes part in the formation of the fibrin plug (clot)
-it catalyzes the cross-linking process of Factor Ia (fibrin)

-click here to view an image of the clotting cascade

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References:

Goodman & Gilman's: The Pharmacologic Basis Of Therapeutics - 10th Edition - 2001. Chapter 55.