Detection of von Willebrand factor-cleaving protease (ADAMTS-13) in human platelets.

The hemostatic activity of von Willebrand factor (vWF) is strongly dependent on its multimeric structure, with the highest activity in 'unusually large' multimers secreted from endothelial cells. The multimeric structure is regulated by a plasma protease, vWF-cleaving protease (vWF-CP, or ADAMTS-13). ADAMTS-13 mRNA is variably expressed in liver and other tissues.