Potently inhibits platelet aggregation induced by ADP (IC(50)=157 nM, complete inhibition at 514 nM). Also inhibits platelet aggregation induced by collagen and by the thrombin receptor peptide SFLLRNP. Is a potent antagonist of the fibrinogen receptor glycoprotein IIb-IIIa (ITGA2B/ITGB3) and the vitronectin receptor alpha-v/beta-3 (ITGAV/ITGB3). Expressed by salivary glands. Contains 2 disulfide bonds.