Characterization of single and compound ADAMTS13 variants. (A) Schematic domain organization of full-length ADAMTS13 showing a signal peptide (S), metalloprotease domain (M), disintegrin domain (D), 8 TSP1 repeats (1-8), Cys-rich domain (C) and spacer domain (Spa), as well as 2 CUB domains (C1 and C2; top), surface representation of exosite 3 and adjacent residues in the spacer domain of ADAMTS13 (left), and names of various ADAMTS13 variants with amino acid substitution (right). (B) Western blotting with anti-V5 detects recombinant WT and variants in the conditioned medium (50 ng per lane). Arrowhead indicates full-length protein of ADAMTS13 WT and variants (∼ 195 kDa) with little degradation. (C) Relative specific activity of ADAMTS13 variants compared with WT. Data are mean ± SD (n = 3). **P < .001, statistically highly significant.