title: Tick anticoagulant peptide (TAP) is a novel inhibitor of blood coagulation factor Xa.
abstract: A low molecular weight serine protease inhibitor (TAP) was purified from extracts of the soft tick, Ornithodoros moubata. The peptide is a slow, tight-binding inhibitor, specific for factor Xa (Ki = 0.588 +/- 0.054 nM). The inhibitor also acts as an anticoagulant in several human plasma clotting assays in vitro. Its amino acid sequence (60 residues) has limited homology to the Kunitz-type inhibitors. However, unlike other inhibitors of this class, TAP inhibits only factor Xa. It had no effect at a 300-fold molar excess on factor VIIa, kallikrein, trypsin, chymotrypsin, thrombin, urokinase, plasmin, tissue plasminogen activator, elastase, or Staphylococcus aureus V8 protease. TAP's specificity and size suggest that it may have therapeutic value as an anticoagulant.
authors.affiliation: Biological Chemistry Department, Merck Sharp & Dohme Research Laboratories, West Point, PA 19486.
authors.forename: L
authors.initials: L
authors.lastname: Waxman
authors.forename: D E
authors.initials: DE
authors.lastname: Smith
authors.forename: K E
authors.initials: KE
authors.lastname: Arcuri
authors.forename: G P
authors.initials: GP
authors.lastname: Vlasuk
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D060829:Arthropod Proteins; D001780:Blood Coagulation Tests; D002850:Chromatography, Gel; D065427:Factor Xa Inhibitors; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D007700:Kinetics; D008969:Molecular Sequence Data; D010455:Peptides / Q000302:isolation & purification* / Q000494:pharmacology; D012689:Sequence Homology, Nucleic Acid; D015842:Serine Proteinase Inhibitors / Q000302:isolation & purification*; D013987:Ticks / Q000032:analysis*
chemical_list: D060829:Arthropod Proteins; D065427:Factor Xa Inhibitors; D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D015842:Serine Proteinase Inhibitors; C063967:tick anticoagulant peptide