This platelet aggregation activation inhibitor (MW = 7700.52 g/mol; CAS 135402-55-0; Accession Number = P22827; Sequence: EAGEECDCGSP ENPCCDAATCKLRPGAQCADGLCCDQCRFMKKGTVCRVAKGDWN DDTCTGQSADCPRNGLYG) was isolated from the venom of the Southeastern Pigmy Rattlesnake (Sistrurus miliarius barbouri), the only of 52 venoms specific for integrin GPIIb-IIIa versus other integrins. Barbourin is highly homologous to other peptides of the viper venom GPIIb-IIIa antagonist family, but contains a Lys-Gly-Asp (KGD) in place of the canonical Arg-Gly-Asp (RGD) sequence needed to inhibit receptor function. Barbourin represents a new structural model for designing potent and GPIIb IIIa-specific, platelet aggregation inhibitors (See Eptifibatide for details on Mechanism of Action).
