Human Factor XIa

Prepared from Human Factor XI using Human Factor Xlla. This Xlla was removed using a corn trypsin inhibitor column. Complete activation is observed by SDS-PAGE. Factor XI, through the contact factor pathway cascade, is activated to Factor XIa via Factor Xlla and High Molecular Weight Kininogen. During activation by Factor Xlla and HK, FXI undergoes proteolytic cleavage in which the Mr=80,000 chain reportedly is cleaved to a heavy and light chain with Mr of about 48,000 and 33,000. This Factor XIa is responsible for the activation of Factor IX to Factor IXa. Unlike other examples of activation of Vitamin K-dependent blood-clotting proteins, Factor XIa proteolysis of Factor IX does not require membrane surfaces.

Buffer composition = 4 mM Sodium Acetate-HCl/0.15 M NaCl/pH 5.3

*Extinction Coefficient (1%) = 13.1

Molecular Weight = 160,000 daltons