Free thiol groups in von Willebrand factor (VWF) are required for its full function under physiological flow conditions.

Introduction: von Willebrand factor (VWF) is rich in cysteine; next to important structural disulfide bonds, free thiol groups are present. Free thiols on the surface of plasmatic VWF have been shown to play a role in VWF self-association and in platelet binding under pathologically high levels of shear stress. The present study explores the role of VWF free thiol groups under physiological levels of shear stress and in interactions with collagen and platelet-GPIbα receptor.

ADAMTS13 content and VWF multimer and triplet structure in commercially available VWF/FVIII concentrates.

ADAMTS13 is a metalloproteinase that cleaves von Willebrand factor (VWF) into smaller multimers in vivo. This cleavage creates both the typical multimeric size distribution and the characteristic triplet band distribution of VWF. Here we analysed ADAMTS13 content, VWF multimeric size distribution and VWF triplet structure in five commercial VWF/factor VIII (FVIII) concentrates.

Distinct role of von Willebrand factor triplet bands in glycoprotein Ib-dependent platelet adhesion and thrombus formation under flow.

Multimeric glycoprotein von Willebrand factor (VWF) exhibits a unique triplet structure of individual oligomers, resulting from ADAMTS-13 (a disintegrin and metalloproteinase with thrombospondin type 1 motifs 13) cleavage. The faster and slower migrating triplet bands of a given VWF multimer have one shorter or longer N-terminal peptide sequence, respectively. Within this peptide sequence, the A1 domain regulates interaction of VWF with platelet glycoprotein (GP)Ib.

Flow-based measurements of von Willebrand factor (VWF) function: binding to collagen and platelet adhesion under physiological shear rate.

Introduction: VWF circulates in plasma as a series of heterogeneous multimers, mediating platelet tethering, translocation and finally adhesion to areas of injured endothelium under physiological high arterial blood flow. VWF-platelet binding requires conformational changes in VWF, which are induced by immobilization and shear. Because of unavailability of a simple flow-based measurement system, VWF activity assays are generally performed under static conditions.