Activated Factor VIII

Activated form of Factor VIII. The B-domain of Factor VIII is proteolytically cleaved by Thrombin to form Factor VIIIa. Factor VIIIa exists as a non-covalent dimer in a metal-linked (probably Calcium) complex and functions as a cofactor in the enzymatic activation of Factor X by Factor IXa. Factor VIIIa is similar in structure and generation to Factor Va.