The Asp272–Glu282 Region of Platelet Glycoprotein Ibα Interacts with the Heparin-binding Site of α-Thrombin and Protects the Enzyme from the Heparin-catalyzed Inhibition by Antithrombin III*

Platelet glycoprotein Ib (GpIb) mediates interaction with both von Willebrand factor and thrombin. Thrombin binds to GpIb via its heparin-binding site (HBS) (De Candia, E., De Cristofaro, R., De Marco, L., Mazzucato, M., Picozzi, M., and Landolfi, R. (1997) Thromb. Haemostasis 77, 735-740; De Cristofaro, R., De Candia, E., Croce, G., Morosetti, R., and Landolfi, R. (1998) Biochem. J. 332, 643-650). To identify the thrombin-binding domain on …