PolyP binds to fibrinogen and soluble fibrin. (A) Fibrinogen (10 μg) was incubated with zirconia beads coated with either polyP₆₅ or bovine serum albumin (BSA). The starting material (SM), flow-through (FT), low-salt (LS), and high-salt (HS) washes were subjected to sodium dodecyl sulfate–polyacrylamide gel electrophoresis on 4% to 12% NuPAGE gels with MOPS running buffer and blotted with an antibody to fibrinogen. (B) PolyP₆₅ was incubated with 10 μg of soluble fibrin (SF), fibrinogen (FG), or buffer alone for 10 minutes before separating on 6% Tris-glycine gels for 2.5 hours under native conditions. The gels were stained with toluidine blue O that binds polyP. Free polyP₆₅ migrates with the dye front and cannot be visualized.