FIGURE 4.

The C4BP-plasminogen interaction is mediated by lysine residues and is partially ionic and hydrophobic in nature. A, microtiter plates were coated with plasminogen (10 μg/ml) and a constant amount of C4BP-PS or rC4BP was added in the presence of increasing concentrations of the lysine analog ϵ-ACA. Binding of C4BP-PS (B–D) or rC4BP (B and D) was analyzed under increasing amounts of NaCl (B), NaBr (C), or ethylene glycol (D). Bound C4BP was detected using a specific polyclonal Abs. Dotted line represents the Ab background. Data represent mean ± S.D. of three independent experiments conducted in duplicates. Statistical significance was calculated using one-way analysis of variance and Dunnett's post-test to compare the binding in the absence of inhibitor; ns, not significant; *, p < 0.05; **, p < 0.01; ***, p < 0.001.