該基因編碼凝血因子xiia亞單位凝血因子xiii是凝血級聯反應中最后被激活的酶原。血漿因子XIII是由2個a亞基和2個B亞基組成的異四聚體a亞基具有催化功能，b亞基不具有酶活性，可作為等離子體載體分子。血小板因子xiii僅由2個a亞單位組成，與血漿來源相同。在凝血酶和鈣離子的存在下，血漿因子xiii分解其b亞單位，并產生與血小板因子xiii相同的活性酶因子xiia。這種酶作為轉谷氨酰胺酶，催化纖維蛋白分子間的γ-谷氨酰-ε-賴氨酸交聯形成，從而穩定纖維蛋白凝塊它還將α-2-纖溶酶抑制劑或纖維粘連蛋白與纖維蛋白的α鏈交聯因子xiii缺陷分為兩類：i型缺陷，其特征是a和b亞單位均缺失；ii型缺陷，其特征是a亞單位單獨缺失。這些缺陷會導致終身出血傾向、傷口愈合不良和習慣性流產。[由RefSeq提供，2008年7月]
This gene encodes the coagulation factor XIII A subunit. Coagulation factor XIII is the last zymogen to become activated in the blood coagulation cascade. Plasma factor XIII is a heterotetramer composed of 2 A subunits and 2 B subunits. The A subunits have catalytic function, and the B subunits do not have enzymatic activity and may serve as plasma carrier molecules. Platelet factor XIII is comprised only of 2 A subunits, which are identical to those of plasma origin. Upon cleavage of the activation peptide by thrombin and in the presence of calcium ion, the plasma factor XIII dissociates its B subunits and yields the same active enzyme, factor XIIIa, as platelet factor XIII. This enzyme acts as a transglutaminase to catalyze the formation of gamma-glutamyl-epsilon-lysine crosslinking between fibrin molecules, thus stabilizing the fibrin clot. It also crosslinks alpha-2-plasmin inhibitor, or fibronectin, to the alpha chains of fibrin. Factor XIII deficiency is classified into two categories: type I deficiency, characterized by the lack of both the A and B subunits; and type II deficiency, characterized by the lack of the A subunit alone. These defects can result in a lifelong bleeding tendency, defective wound healing, and habitual abortion. [provided by RefSeq, Jul 2008]