PolyP-induced changes in fibrin formation and structure. (A) Fibrinogen (2.4μM) was clotted in the absence (gray line) and presence (black line) of polyP₆₅ (325μM) by an activation mix of thrombin (0.25 U/mL) and CaCl₂ (5mM). The turbidity was monitored at 340 nm every 12 seconds for 30 minutes, and the results are expressed as mean ± SEM (n = 4). (B) Fibrinopeptide release from fibrinogen during polymerization with thrombin (0.2 U/mL) and CaCl₂ (5mM) was monitored over time by reverse-phase high-performance liquid chromatography (HPLC) in the absence (open symbols) and presence (closed symbols) of polyP₆₅ (325μM). The concentration of fibrinopeptide A (circles) and fibrinopeptide B (triangles) at each time point is expressed as a fraction of maximal release ([FP]/[FP]_max, so that complete release is equal to 1). The inset shows the linear part of the curve.