SDS-(3.5% to 20% gradient) PAGE of purified fragments produced by proteolysis of vWF. (Left panel) Fragments were loaded at 10 μg/well. After migration the gel was stained using Coomassie blue. (Right panel) The fragments were loaded at 5 μg/well. After migration the proteins were electrotransfered on a nitrocellulose sheet, stained by incubating with ¹²⁵I-purified bitiscetin, and showed by autoradiography. Fragments were SpI (lanes 1 and 6); SpII (lanes 2 and 7); T116 (lanes 3 and 8); 39/34 kD (lanes 4 and 9); and SpIII (lanes 5 and 10).