ADAMTS13 degradation of type 2A variant VWF proteins. VWF in the conditioned medium of transiently transfected HEK293T cells was digested with rhuADAMTS13 and analyzed by electrophoresis in 2% SDS-agarose gels and immunoblotted as described in “Multimer analysis.” All samples were run on the same gel and lanes were removed for clarity, as denoted by white space. Each variant was digested with BaCl₂ to activate the rhuADAMTS13 (+B), or in the presence of EDTA to prevent activation of huADAMTS13 (+E). Sample set 1 shows WT-VWF, which is cleaved minimally by rhuADAMTS13. Sample sets 2-4 show type 2A mutations that displayed a full range of VWF multimers (I1568N, G1579R, and G1631D) and had increased susceptibility to cleavage by rhuADAMTS13. Sample sets 5-7 show type 2A VWD mutations involving cysteines (C1272S, C1272Y, and C1099P). C1272S and C1272Y may have increased proteolysis, whereas C1099P does have increased proteolysis.