Factor Xia Protein

Proteolytic Activation of Factor XI: Although factor XI can bind independently to negatively charged surfaces, proteolysis by factor XIIa can only occur in the presence of surface-bound high molecular weight kininogen (HMWKa). The bound HMWKa is susceptible to proteolysis by the newly generated factor XIa which results in a loss of its biological activity (HMWKi). Factor XIa catalyzes the proteolytic conversion of factor IX to factor IXa either in solution phase or when bound to a negatively charged surface.

Factor XIa, like its precursor factor XI, remains in complex with HMWK (4). In complex form, factor XIa/HMWK is capable of activating factor XII to factor XIIa and prekallikrein to kallikrein. Additionally, in the complexed form, factor XIa is less affected by protease inhibitors (5). The major plasma inhibitor of factor XIa is a1-antitrypsin and then to a much lesser extent, antithrombin-III (5,6). While in the complexed form, factor XIa may catalyze the proteolysis of HMWK, yielding a biologically inactive form of HMWK (HMWKi), thus allowing dissociation of the Factor XIa/HMWKi complex. Either free factor XIa or the factor XIa/HMWK complex catalyzes the proteolytic conversion of factor IX to factor IXa.

Small volumes of Factor XIa protein vial(s) may occasionally become entrapped in the seal of the product vial during shipment and storage. If necessary, briefly centrifuge the vial on a tabletop centrifuge to dislodge any liquid in the container`s cap. Certain products may require to ship with dry ice and additional dry ice fee may apply.

MBS634636 is a protein targeting Factor XIa. Also known as Factor XIa, Human. Host: Human plasma.