AAPP

This protein, anopheline anti-platelet protein (AAPP), is found to bind directly to type-I and type-III collagen and blocks platelet adhesion with an IC50 of ∼30 nm. Collagen is only exposed to circulating plasma proteins at sites of damage to blood vessels. It causes platelets to aggregate through the action of the plasma protein von Willebrand factor, which initiates platelet tethering and blood clotting at sites of vascular injury. Activated platelets subsequently adhere directly to subendothelial collagen through glycoprotein 1b so that blocking exposed collagen prevents the initiation and progression of platelet aggregation.