Factor XIIIa (Fibrinoligase, Plasma Transglutaminase, Fibrin Stabilizing Factor)

Factor XIII is a beta globulin found in plasma and is composed of two subunits. Coagulation factor XIII is the last zymogen to become activated in the blood coagulation cascade. Factor XIIIa is the catalytic subunit and is a dimer of molecular weight 160kD. 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 activation by the 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. Factor XIIIa is a dermal dendrocyte marker and shows variable reaction with these types of tumors. It can be used for histiocytic phenotyping and has been reported to mark capillary hemangiomas and tumors of the central nervous system. Applications: Suitable for use in ELISA and Immunohistochemistry. Other applications not tested. Recommended Dilutions: Immunohistochemistry (Frozen/paraffin): Use ABC method. Incubate 30 minutes at RT. Optimal dilutions to be determined by the researcher. Positive Control: Placenta Storage and Stability: May be stored at 4 degrees C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20 degrees C. Aliquots are stable for 12 months. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.