title: A potent antiplatelet peptide, triflavin, from Trimeresurus flavoviridis snake venom.
abstract: The interaction of fibrinogen with its receptors on platelet surfaces leads to platelet aggregation. A snake-venom peptide, trigramin, has previously been demonstrated to inhibit platelet aggregation by acting as a fibrinogen-receptor antagonist. By means of gel filtration, ionic-exchange chromatography and reverse-phase h.p.l.c., a potent platelet-aggregation inhibitor, triflavin, has now been purified from the venom of Trimeresurus flavoviridis. The purified triflavin is a single-chain polypeptide, consisting of about 71 amino acid residues with a molecular mass of 7600 Da, and its N-terminal sequence is Gly-Glu-Glu-Cys-Asp. Triflavin dose-dependently inhibited human platelet aggregation stimulated by ADP, adrenaline, collagen, thrombin or prostaglandin endoperoxide analogue U46619 in preparations of platelet-rich plasma, platelet suspension and whole blood. Its IC50 ranged from 38 to 84 nM, depending on the aggregation inducer used and the platelet preparation. However, triflavin apparently did not affect the platelet shape change and ATP-release reactions caused by these agonists. Triflavin inhibited fibrinogen-induced aggregation of human elastase-treated platelets in a dose-dependent manner, indicating that it directly interferes with the binding of fibrinogen to its receptors on platelet membranes exposed by elastase treatment. Additionally, triflavin dose-dependently blocked 125I-labelled fibrinogen binding to ADP-activated platelets. In conclusion, triflavin inhibits platelet aggregation through the blockade of fibrinogen binding to fibrinogen receptors on platelet membranes.
authors.affiliation: Pharmacological Institute, College of Medicine, National Taiwan University, Taipei.
authors.forename: T F
authors.initials: TF
authors.lastname: Huang
authors.forename: J R
authors.initials: JR
authors.lastname: Sheu
authors.forename: C M
authors.initials: CM
authors.lastname: Teng
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000097:blood; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003094:Collagen / Q000494:pharmacology; D003435:Crotalid Venoms / Q000032:analysis*; D004591:Electrophoresis, Polyacrylamide Gel; D005340:Fibrinogen / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D008969:Molecular Sequence Data; D010455:Peptides / Q000302:isolation & purification*; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000302:isolation & purification*; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism; D012911:Snakes
chemical_list: D000596:Amino Acids; D003435:Crotalid Venoms; D010455:Peptides; D010975:Platelet Aggregation Inhibitors; D010980:Platelet Membrane Glycoproteins; C029748:Trimeresurus venoms; C070025:triflavin; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D005340:Fibrinogen; D003094:Collagen