Interaction of antithrombin III in purified solution and in plasma with insoluble modified polystyrene

Additional data are presented on the adsorption of antithrombin III (ATIII) from purified solution and plasma, to insoluble polystyrene resins bearing sulfonate and various amino acid sulfamide groups. In previous studies of the interaction of ATIII with these resins, it was shown that monolayers are formed and the affinity constants are of the order of 3 × 105 L mol−1.To study the adsorption of ATIII from purified solution or plasma, the resins were exposed to a solution of the antiprotease or to citrate-anticoagulated human plasma for 3 h. Adsorbed proteins were then eluted sequentially by l M Tris buffer and 4% SDS solution, and examined by SDS PAGE and Western blot analysis using an anti-ATIII antiserum. A consistent finding for all resins is the presence of ATIII in all the eluates. High molecular weight components which are reactive to anti-ATIII antibody were also consistently found. These components do not appear to be ATIII contact factor complexes, but Cls-ATIII complexes.