Abstract Platelet GpIIb/IIIa is a member of the integrin family of structurally related adhesion receptors, and adhesive proteins, such as fibrinogen. Ligand binding requires platelet activation by an agonist to convert the receptor to a state where it is capable to bind the ligand. In addition to this a modification, induction of the surface expression and ligand-binding function of an additional pool of GpIIb/ IIIa derived from α-granuler membranes and/or surface-connecting open canalicular system are established. Fibrinogen binding to platelets appears to be important for platelet aggregation. Platelet aggregation is essential for normal hemostasis and also plays a role in thrombosis. In this study, we purified GpIIb/IIIa on a single step from normal human platelets by GRGDSP-affinity chromatography. In addition, studies on the characterization of the binding properties to GIIb/ IIIa of the specific ligands were carried out with the purified GpIIb/IIIa complex. Özet Integrin ailesinin bir üyesi olan GpIIb/IIIa, yapisal olarak fibrinojen gibi adeziv proteinlerle iliskili trombosit adezyon reseptörüdür. Ligand baglamak için bir agoniste ihtiyaç duyar ve yapisinda konformasyonel bir degisiklige ugrar. Bu modifikasyona ek olarak, trombosit α-granüllerinden ve yüzey baglantili açik kanaliküler sistemden GpIIb/IIIa havuzuna katki saglanarak, ligand-baglama fonksiyonu ve yüzey expresyonu artar. Trombositlere fibrinojen baglanmasi trombosit agregasyonu için önemlidir. Trombosit agregasyonu normal hemostas için temeldir ve trombozda da rol oynamaktadir. Bu çalismada, saglikli insan trombositlerinden GRGDSP-afinite kromatografisi ile GpIIb/IIIa tek adimda saflastirildi. Saflastirilmis GpIIb/IIIa kompleksi ile, GpIIb/IIIa’ya spesifik ligandlarla baglanma özelliklerinin çalismalari yapildi.

Keywords: GpIIb/IIIa, affinity chromatography, platelet fibrinogen receptor