FIGURE 4.

Chemical cross-linking of factor C with dimethyl adipimidate on lipopolysaccharides. A, wild-type factor C (8.6 nm) was cross-linked with dimethyl adipimidate at several concentrations of lipopolysaccharides and subjected to Western blotting. Data are representative of three independent experiments. B, the density of cross-linked wild-type factor C molecules on the PVDF membrane was analyzed with Image J software. The vertical axis shows relative densities against that of wild-type factor C cross-linked at 5.9 nm lipopolysaccharides. Data are the mean ± S.D. of three independent experiments. C, wild-type factor C (8.6 nm) was incubated with several concentrations of lipopolysaccharides and assayed with Boc-Val-Pro-Arg-pNA. The unit of the amidase activity was defined as micromole of the digested substrate per min. The specific activity was expressed as units per nmol of factor C. Data are the mean ± S.D. of three independent experiments.