(A) Gel analysis of proteins purified on recombinant CRISP3-coated cyanogen bromide resin showed CRISP3 interaction with A1BG from both human (lane 3, ~85 kDa band) and bovine (lane 3, ~65 kDa band) serum, as confirmed by mass spectrometry. Elution control samples were loaded as follows; lane 1: uncoated beads incubated with serum, lane 2: CRISP3-coated beads incubated with PBS, lane 3: CRISP3-coated beads incubated with serum. In the case of human serum, all eluted proteins in lane 3 other than A1BG bound non-specifically to the beads (compare with lane 1). (B) Denatured CRISP3 (lane 3) was unable to bind A1BG. Full length gels are available under supplementary data; gels were run under the same conditions.