Factor XIII, fibrin and collagen.

It has been demonstrated that activated factor XIII may catalyze the formation of covalent cross-links between fibrin and collagen. This is shown by the disappearance of the gamma-gamma dimer band in PAA-SDS gel electrophoresis when fibrinogen is clotted in presence of collagen, factor XIII and Ca ions, and by the binding of labeled fibrinogen. This reaction may explain the outstanding physiological importance of factor XIII.