Purification of the porcine platelet GP IIb-IIIa complex and the propolypeptide of von Willebrand factor.
Platelet membrane glycoproteins (GP) are involved in platelet adhesion and aggregation. The glycoprotein IIb-IIa complex (GP IIb-IIIa) is a Ca2+-dependent heterodimer that binds fibrinogen and other adhesive proteins, thereby mediating platelet aggregation and adhesion. We have purified two major glycoproteins from pig platelets by Concanavalin A-Sepharose, Heparin-Sepharose and Sephacryl S-300 HR chromatography (Fitzgerald et al. Anal Biochem, 1985): i) the GP IIb-IIIa complex, GP IIb Mr = 140,000 and GP IIIa a single chain of Mr = 95,000-100,000; and ii) a predominant glycoprotein of high molecular weight, the propolypeptide of von Willebrand factor (Mr = 80,000-100,000). Western-blot analysis of the purified GP IIb-IIIa showed that only certain monoclonal antibodies against the human receptor specifically recognize the porcine complex. Differences between the porcine and human GP IIb-IIIa glycoproteins could partially explain the decreased inhibitory effects of GP IIb/IIIa-antagonists (against the human receptor) in porcine platelets.
Royo
T
T
Research Institute Sant Pau, Barcelona, Spain.
Vidal
M
M
Badimon
L
L
D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D003208:Concanavalin A; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D006735:Horseradish Peroxidase; D006801:Humans; D007150:Immunohistochemistry; D008969:Molecular Sequence Data; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000302:isolation & purification*; D011498:Protein Precursors / Q000302:isolation & purification*; D017386:Sequence Homology, Amino Acid; D013552:Swine; D014841:von Willebrand Factor / Q000302:isolation & purification*
D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D011498:Protein Precursors; D014841:von Willebrand Factor; D003208:Concanavalin A; D006735:Horseradish Peroxidase