FXIII
Factor XIII (FXIII), also known as fibrin-stabilizing factor, is a zymogen in blood that stabilizes forming clots by cross-linking fibrin strands. In plasma, FXIII circulates as a heterotetramer (FXIII-A2B2) composed of two catalytic A subunits and two regulatory B subunits. Activation occurs when thrombin cleaves an activation peptide on the A subunits in the presence of calcium, causing dissociation of the B subunits and formation of the active enzyme FXIIIa, a calcium-dependent transglutaminase.
FXIIIa catalyzes the formation of covalent bonds between glutamine and lysine residues, reinforcing the fibrin network.
Clinical aspects: FXIII deficiency is rare and can be congenital (often autosomal recessive) or acquired. Deficiency
Overall, FXIII plays a key role in clot maturation and tissue integrity, extending its influence beyond coagulation