Calibration of the vWF-cleaving protease assay. The 1:20 dilution of NHP was denoted as 100% activity. TBS/1 mmol/L Pefabloc was used to prepare further dilutions (1:40 to 1:640). The lane denoted as 0.00 represents multimeric distribution of the vWF substrate that had been incubated with dilution buffer alone.