Human Factor XIII is a tetramer composed of two pairs of chains held together by noncovalent bonds. After activation of the zymogen via Thrombin to its active enzyme form, Factor XIIIa is responsible for catalyzing the formation of covalent bridges between fibrin units to increase the elasticity of the clot network. The resulting cross-linked fibrin is very insoluble and resistant to lysis.
Buffer composition =50 mM Tris-HCl/0.1 M NaCl/1 mM EDTA/10u/mL aprotinin/20% glycerol/pH 7.5Extinction Coefficient (1%)=13.8Molecular Weight = 320,000 daltons