| Description | Purity ≥90%, as determined by SDS-PAGE under reducing conditions and visualized by silver stain. Endotoxin: ≤1.0EU/ug (LAL). Platelet glycoprotein Ib alpha chain (GPIb a), also known as CD42ba, is a 145kD type I transmembrane protein that is a member of the leucine-rich repeat (LRR) family of ligand binding proteins.1-3 It is expressed by platelets as the ligand-binding subunit of the platelet GPIb-IX-V complex.4 Human GPIb a contains a 16 amino acid (aa) signal sequence, a 489 aa extracellular domain (ECD), a 21-aa transmembrane domain, and a 100 aa cytoplasmic region. The ECD contains 8 LRRs, with # 2, 3 and 4 having been demonstrated to regulate shear-dependent adhesion to von Willebrand factor (vWF).5, 6 The LRRs are followed by a thrombin-binding anionic region that includes three sulfated tyrosines, a sialomucin domain with N- and O-linked carbohydrates, and two cysteines near the membrane that allow dimerization with GP1bb.1-6 Four human isoforms with 1 to 4 repeats of aa 398-41 |
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