title: Surface adsorption of factor XI. Association of adsorption sites with the heavy chain of activated factor XI.
abstract: These experiments study surface adsorption of native and activated factor XI using purified radiolabelled human factor XI and trypsin activated factor XI. Both forms of factor XI adsorb not only to glass but also to polypropylene, polyethylene and polystyrene. Albumin (10 mg/ml) markedly reduces adsorption to plastics but not to glass. Sodium dodecyl sulfate prevents adsorption to all surfaces tested. Reduction of 125I-activated factor XI in the presence of sodium dodecyl sulfate yields labelled chains of molecular weight of about 46,000 (heavy chain), 37,000 (light chain) and a further breakdown product of about 26,000. Reduction of activated factor XI in glass or plastic in the absence of sodium dodecyl sulfate yields only light chain and breakdown product in solution; heavy chain is removed by adsorption. Therefore, we conclude that the adsorption site (s) in trypsin activated factor XI and presumably also in native factor XI is (are) located in the heavy chain subunit of the molecule.
mesh_terms: D000327:Adsorption; D004591:Electrophoresis, Polyacrylamide Gel; D005172:Factor XI / Q000378:metabolism*; D006801:Humans; D014357:Trypsin / Q000494:pharmacology
chemical_list: D005172:Factor XI; D014357:Trypsin