title: The N-DSK gamma-chain binds to immunoprecipitated GP IIb-IIIa.
abstract: The CNBr-split N-terminal disulphide knot of the fibrinogen molecule (N-DSK) binds to ADP-stimulated gel-filtered platelets and immunoprecipitated fibrinogen receptor. To investigate which part of the N-DSK molecule that is involved in this binding, the glycoprotein IIb-IIIa complex (the fibrinogen receptor) was immunoprecipitated in crossed immunoelectrophoresis of Triton X-100 extracts of platelets against rabbit antibodies to whole platelet proteins. The immunoelectrophoresis plates were incubated with solubilized, carboxymethylated 125I-labelled A alpha -, B beta - or gamma-chains of N-DSK, and investigated for binding by autoradiography. The N-DSK gamma-chain, but not the A alpha - or B beta -chains demonstrated binding to the GP IIb-IIIa complex. These results show that the fibrinogen molecule contains a third sequence of amino acids, in addition to the two previously reported ones that can be involved in binding of fibrinogen to the fibrinogen receptor on the platelets.
mesh_terms: D001665:Binding Sites; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism*; D005340:Fibrinogen / Q000378:metabolism; D006801:Humans; D007123:Immunoelectrophoresis, Two-Dimensional; D007457:Iodine Radioisotopes; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism*; D011485:Protein Binding
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; D007457:Iodine Radioisotopes; D010980:Platelet Membrane Glycoproteins; D005340:Fibrinogen