title: Purification and characterization of an antiplatelet peptide, arietin, from Bitis arietans venom.
abstract: By means of Fractogel TSK-50, CM-Sephadex C-50 column chromatography, gel filtrations on Sephadex G-75 and Sephacryl S-200 columns and reverse-phase HPLC, an antiplatelet peptide, arietin, was purified from venom of Bitis arietans. Arietin was shown to be an Arg-Gly-Asp-containing peptide with a NH2-terminus, Ser-Pro-Pro-Val-Cys-Gly-Asn-Lys- (Mr 8500). Arietin dose-dependently inhibited aggregation of human platelet suspension stimulated by ADP, thrombin, collagen and U46619 with IC50, 1.3-2.7.10(-7) M, while it had no effect on the initial shape changes and only slightly affected ATP release of platelets caused by thrombin and collagen. Arietin also blocked platelet aggregation in platelet-rich plasma and whole blood, and inhibited thrombin-induced clot retraction of platelet-rich plasma. Furthermore, arietin (6.5.10(-8) M) completely blocked the fibrinogen-induced aggregation of elastase-treated platelets, indicating that arietin interferes with the fibrinogen binding to fibrinogen receptors on platelet membranes. In conclusion, arietin, an Arg-Gly-Asp-containing peptide, inhibits platelet aggregation probably through the blockade of fibrinogen binding to the activated platelets.
authors.affiliation: Pharmacological Institute, college of Medicine, National Taiwan University, Taipei.
authors.forename: T F
authors.initials: TF
authors.lastname: Huang
authors.forename: W J
authors.initials: WJ
authors.lastname: Wang
authors.forename: C M
authors.initials: CM
authors.lastname: Teng
authors.forename: C S
authors.initials: CS
authors.lastname: Liu
authors.forename: C
authors.initials: C
authors.lastname: Ouyang
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001780:Blood Coagulation Tests; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D010975:Platelet Aggregation Inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D010980:Platelet Membrane Glycoproteins / Q000037:antagonists & inhibitors; D014757:Viper Venoms / Q000737:chemistry*
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D010975:Platelet Aggregation Inhibitors; D010980:Platelet Membrane Glycoproteins; D014757:Viper Venoms; C069270:arietin; D000244:Adenosine Diphosphate