Adsorption from plasma and buffer of single- and two-chain high molecular weight kininogen to glass and sulfonated polyurethane surfaces

The adsorption of high molecular weight kininogen (HK) in its single-chain (SCHK) and two-chain (TCHK) forms from single protein solutions, plasma, and kininogen-deficient plasma, to glass and sulfonated polyurethane surfaces is reported. Using radiolabelling methods, it was found that in a single protein buffered system there was no difference in the adsorbed amounts of SCHK and TCHK over the concentration range 5-100 microg ml(-1) (similar to that in plasma). The adsorption of the two forms from normal plasma was also the same. However, immunoblots using an anti-HK antibody indicated that over the 2 h adsorption time, much of the SCHK present in the plasma was converted to TCHK: the band at 120 kD representative of intact SCHK disappeared, and bands at 56 and 46 kD representative of the heavy and light chains of TCHK were generated. To prevent conversion of SCHK to TCHK, the kallikrein inhibitor aprotinin (or in some cases a protease inhibitor cocktail), was added to the plasma in subsequent experiments. In addition, kininogen-deficient plasma was used (with either labelled SCHK or TCHK added) to avoid ambiguity in the tracer-population relationship. It was again found that there was no difference in the amounts of SCHK and TCHK adsorbed to glass and the sulfonated polyurethanes. The significance of these findings in relation to the reported anti-cell adhesion properties of adsorbed HK is discussed.