ABSTRACT
Blood coagulation factor VIII circulates in a complex with von Willebrand factor (vWF) within the vascular space. von Willebrand factor is synthesized as a monomer (pre-pro-vWF), which then undergoes considerable posttranslational modi€cation including dimerization followed by oligomerization.1 vWF polymers are stored in Weibel-Palade bodies in endothelial cells and platelet α-granules prior to secretion. The large vWF oligomers are processed by limited proteolysis by ADAMTS-13 (a disintegrin and metalloproteinase with thrombospondin motifs-13).2 Failure of proteolytic processing of large vWF oligomers on secretion results in thrombotic thrombocytopenic purpura.3 vWF demonstrates substantial size heterogeneity in plasma.4 The primary function of vWF initiates platelet aggregation at the site of vascular injury.5 vWF also complexes with factor VIII, apparently stabilizing the factor VIII protein.6,7 Binding of vWF to a surface promotes dissociation of factor VIII.8
