families, which include important protease enzymes. The secreted protease ADAMTS13, found in serum, cleaves Von Willebrand factor and acts as a natural, endogenous inhibitor of platelet adhesion and aggregation. ADAM2 (beta-fertilin, the beta-subunit of guinea pig sperm surface protein PH30). PH30 is a protein involved in sperm-egg fusion. The beta subunit contains a disintegrin at the N-terminal extremity. ADAM7 (Mammalian epididymial apical protein 1, EAP I). ADAM7 is associated with the sperm membrane and may play a role in sperm maturation. Structurally, ADAM7 consists of an N-terminal domain, followed by a zinc metalloproteinase domain, a disintegrin domain, and a large C-terminal domain that contains a transmembrane region. See also ADAM Protein Evolution of snake venom References External links Animal proteins Venomous snakes