The ADAMTS-13 CUB domains were expressed in CHO cells and recombinant proteins were immunoblotted by a monoclonal antibody against Myc-tag (both CUB domains) or a goat antibody made against a synthetic peptide derived from CUB-1 under non-reducing (A) and reducing conditions (B). CUB-1 and CUB-2 were co-expressed in CHO cells and immunoblotted under reducing and non-reducing conditions by antibodies against Myc-tag or clone 158, which only binds CUB-1 (C, R: reduced; NR: non-reduced). The activated thiol beads captured rADAMTS-13 (D, lane 1) and rCUB-1+2 (D, lane 2) that were eluted by DTT and detected by immunoblotting. Recombinant CUB-1 (E, lane 1) and CUB-1C1275S (E, lane 2) were separated on SDS-PAGE under non-reducing conditions and were immunoblotted with Myc antibody. Conversion of C1275 (F, lane 1) to serine (F, lane 2) reduced CUB-1+2 captured by thiol bead by more than 90%. The figure was a representative of 3 ∼11 separate experiments.