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, an d kininogen-deficient plasma, to glass and sulfonated polyurethane surfaces is reported. Using radiolabelling methods, it was found that in a single p rotein buffered system there was no difference in the adsorbed amounts of S CHK and TCHK over the concentration range 5-100 mu g ml(-1) (similar to tha t in plasma). The adsorption of the two forms from normal plasma was also t he 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 conver ted 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 T CHK were generated. To prevent conversion of SCHK to TCHK, the kallikrein i nhibitor aprotinin (or in some cases a protease inhibitor cocktail), was ad ded to the plasma in subsequent experiments. In addition, kininogen-deficie nt plasma was used (with either labelled SCHK or TCHK added) to avoid ambig uity in the tracer-population relationship. It was again found that there w as 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. (C ) 1999 Elsevier Science Ltd. All rights reserved.