<p> Disintegrins are a family of small proteins from viper venoms that function as potent inhibitors of both platelet aggregation and integrin-dependent cell adhesion [<cite idref="PUB00035680"/>, <cite idref="PUB00035681"/>]. Integrin receptors are involved in cell-cell and cell-extracellular matrix interactions, serving as the final common pathway leading to aggregation via formation of platelet-platelet bridges, which are essential in thrombosis and haemostasis. Disintegrins contain an RGD (Arg-Gly-Asp) or KGD (Lys-Gly-Asp) sequence motif that binds specifically to integrin IIb-IIIa receptors on the platelet surface, thereby blocking the binding of fibrinogen to the receptor-glycoprotein complex of activated platelets. Disintegrins act as receptor antagonists, inhibiting aggregation induced by ADP, thrombin, platelet-activating factor and collagen [<cite idref="PUB00035682"/>]. The role of disintegrin in preventing blood coagulation renders it of medical interest, particularly with regard to its use as an anti-coagulant [<cite idref="PUB00035683"/>].</p><p>Disintegrins from different snake species have been characterised: albolabrin, applagin, barbourin, batroxostatin, bitistatin, obtustatin [<cite idref="PUB00027415"/>], schistatin [<cite idref="PUB00035684"/>], echistatin [<cite idref="PUB00030741"/>], elegantin, eristicophin, flavoridin [<cite idref="PUB00026241"/>], halysin, kistrin, tergeminin, salmosin [<cite idref="PUB00026913"/>] and triflavin.</p><p>Disintegrin-like proteins are found in various species ranging from slime mold to humans. Some other proteins known to contain a disintegrin domain are:</p><ul><li>Some snake venom zinc metalloproteinases [<cite idref="PUB00035685"/>] consist of an N-terminal catalytic domain fused to a disintegrin domain. Such is the case for trimerelysin I (HR1B), atrolysin-e (Ht-e) and trigramin. It has been suggested that these proteinases are able to cleave themselves from the disintegrin domains and that the latter may arise from such a post-translational processing.</li><li>The beta-subunit of guinea pig sperm surface protein PH30 [<cite idref="PUB00004116"/>]. PH30 is a protein involved in sperm-egg fusion. The beta subunit contains a disintegrin at the N-terminal extremity.</li><li>Mammalian epididymial apical protein 1 (EAP I) [<cite idref="PUB00000515"/>]. EAP I is associated with the sperm membrane and may play a role in sperm maturation. Structurally, EAP I 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.</li> </ul>