ADAMTS13 assay using wild-type full-length von Willebrand factor (VWF). Wild-type rhuVWF-WT was digested by increasing concentrations of rhuADAMTS13. Although the undigested control (lane 1) lacks a triplet structure of the individual oligomers, these are specifically generated by ADAMTS13 digestion in a dose-dependent manner, paralleled by loss of HMWMs (lanes 2-4). Arrows mark the characteristic outer subbands of VWF. Deletion of the A2 domain of VWF, which contains the specific ADAMTS13 cleavage site, abrogates VWF proteolysis by ADAMTS13 (lane 5). NP indicates normal plasma pool (lane 6).