The effect of surfactants on the interaction of factor XII with surfaces

Factor XII (Hageman factor) binds irreversibly to plastic as well as glass surfaces. In dilute solution this leads to significant losses of protein onto the walls of tubes, etc. This could be prevented most efficiently by the presence of surfactants in solution. Rinsing the surfaces after contact with the protein, or precoating the surfaces were less effective. Triton X-100 was found to be non-denaturing and effective at concentrations as low as 0.001%. In its presence higher specific activities were obtained in spectrophotometric assay. The autoactivation of factor XII exposed to glass was inhibited but not prevented by Triton X-100. Similar effects on the binding and assay of (Pre) kallikrein were also found.