Subscribe to RSS
DOI: 10.1160/TH09-04-0221
Molecular diversity of anticoagulants from haematophagous animals
Publication History
Received:
02 April 2009
Accepted after minor revision:
11 June 2009
Publication Date:
22 November 2017 (online)
Summary
To obtain blood meals, haematophagous animals are armed with potent pharmacological molecules to overcome several of their hosts’ response systems. Among them, a large number of exogenous anticoagulants which target the haemostatic system have been identified and characterised. Studies on these anticoagulants have expanded our knowledge on the blood coagulation system, and provided a valuable source of antithrombotic therapeutic agents. Advances in genomic, transcriptomic, structural and proteomic tools greatly accelerated the discovery and analysis of the exogenous anticoagulants in recent years. The molecular diversity observed in these molecules is huge and is constantly expanding. In this review, we will provide an overview on the structure, function and mechanism of the exogenous anticoagulants from haematophagous animals and rationalise their molecular diversity.
-
References
- 1 Furie B, Furie BC. Mechanisms of thrombus formation. N Engl J Med 2008; 359: 938-949.
- 2 Furie B, Furie BC. In vivo thrombus formation. J Thromb Haemost 2007; 05 (Suppl. 01) 12-17.
- 3 Davie EW. et al. The coagulation cascade: initiation, maintenance, and regulation. Biochemistry 1991; 30: 10363-10370.
- 4 Koh CY, Kini RM. Anticoagulants from hematophagous animals. Expert Rev Hematol 2008; 01: 135-139.
- 5 Ajjan R, Grant PJ. Coagulation and atherothrombotic disease. Atherosclerosis 2006; 186: 240-259.
- 6 Gross PL, Weitz JI. New anticoagulants for treatment of venous thromboembolism. Arterioscler Thromb Vasc Biol 2008; 28: 380-386.
- 7 Eikelboom JW, Hirsh J. Combined antiplatelet and anticoagulant therapy: clinical benefits and risks. J Thromb Haemost 2007; 05 (Suppl. 01) 255-263.
- 8 Wu KK, Matijevic-Aleksic N. Molecular aspects of thrombosis and antithrombotic drugs. Crit Rev Clin Lab Sci 2005; 42: 249-277.
- 9 Melnikova I. The anticoagulants market. Nat Rev Drug Discov 2009; 08: 353-354.
- 10 Gray E. et al. Heparin and low-molecular-weight heparin. Thromb Haemost 2008; 99: 807-818.
- 11 Cranenburg EC. et al. Vitamin K: the coagulation vitamin that became omnipotent. Thromb Haemost 2007; 98: 120-125.
- 12 Weitz JI. Emerging anticoagulants for the treatment of venous thromboembolism. Thromb Haemost 2006; 96: 274-284.
- 13 Greinacher A, Warkentin TE. The direct thrombin inhibitor hirudin. Thromb Haemost 2008; 99: 819-829.
- 14 Warkentin TE. et al. Bivalirudin. Thromb Haemost 2008; 99: 830-839.
- 15 Yeh RW, Jang IK. Argatroban: update. Am Heart J 2006; 151: 1131-1138.
- 16 Eriksson BI. et al. Dabigatran etexilate. Nat Rev Drug Discov 2008; 07: 557-558.
- 17 Abrams PJ, Emerson CR. Rivaroxaban: a novel, oral, direct factor Xa inhibitor. Pharmacotherapy 2009; 29: 167-181.
- 18 Ribeiro JM. Blood-feeding arthropods: live syringes or invertebrate pharmacologists?. Infect Agents Dis 1995; 04: 143-152.
- 19 Ribeiro JM, Francischetti IM. Role of arthropod saliva in blood feeding: sialome and post-sialome perspectives. Annu Rev Entomol 2003; 48: 73-88.
- 20 Salzet M. Anticoagulants and inhibitors of platelet aggregation derived from leeches. FEBS Lett 2001; 492: 187-192.
- 21 Champagne DE. Antihemostatic strategies of blood-feeding arthropods. Curr Drug Targets Cardiovasc Haematol Disord 2004; 04: 375-396.
- 22 Hovius JW. et al. Salivating for knowledge: potential pharmacological agents in tick saliva. PLoS Med 2008; 05: e43.
- 23 Markwardt F. The development of hirudin as an antithrombotic drug. Thromb Res 1994; 74: 1-23.
- 24 Scharf M. et al. Primary structures of new ‘iso-hirudins’. FEBS Lett 1989; 255: 105-110.
- 25 Scacheri E. et al. Novel hirudin variants from the leech Hirudinaria manillensis. Amino acid sequence, cDNA cloning and genomic organization. Eur J Biochem 1993; 214: 295-304.
- 26 Steiner V. et al. Primary structure and function of novel O-glycosylated hirudins from the leech Hirudinaria manillensis . Biochemistry 1992; 31: 2294-2298.
- 27 Stone SR, Hofsteenge J. Kinetics of the inhibition of thrombin by hirudin. Biochemistry 1986; 25: 4622-4628.
- 28 Myles T. et al. Electrostatic steering and ionic tethering in the formation of thrombin-hirudin complexes: the role of the thrombin anion-binding exosite-I. Biochemistry 2001; 40: 4972-4979.
- 29 Clore GM. et al. The conformations of hirudin in solution: a study using nuclear magnetic resonance, distance geometry and restrained molecular dynamics. EMBO J 1987; 06: 529-537.
- 30 Haruyama H, Wuthrich K. Conformation of recombinant desulfatohirudin in aqueous solution determined by nuclear magnetic resonance. Biochemistry 1989; 28: 4301-4312.
- 31 Vitali J. et al. The structure of a complex of bovine alpha-thrombin and recombinant hirudin at 2.8-A resolution. J Biol Chem 1992; 267: 17670-17678.
- 32 Grutter MG. et al. Crystal structure of the thrombin-hirudin complex: a novel mode of serine protease inhibition. EMBO J 1990; 09: 2361-2365.
- 33 Rydel TJ. et al. The structure of a complex of recombinant hirudin and human alpha-thrombin. Science 1990; 249: 277-280.
- 34 Rydel TJ. et al. Refined structure of the hirudinthrombin complex. J Mol Biol 1991; 221: 583-601.
- 35 Liu CC. et al. Crystal structure of a biosynthetic sulfo-hirudin complexed to thrombin. J Am Chem Soc 2007; 129: 10648-10649.
- 36 Bode W. et al. The refined 1.9-A X-ray crystal structure of D-Phe-Pro-Arg chloromethylketone-inhibited human alpha-thrombin: structure analysis, overall structure, electrostatic properties, detailed active-site geometry, and structure-function relationships. Protein Sci 1992; 01: 426-471.
- 37 Schechter I, Berger A. On the size of the active site in proteases. I. Papain. Biochem Biophys Res Commun 1967; 27: 157-162.
- 38 Strube KH. et al. Isolation, sequence analysis, and cloning of haemadin. An anticoagulant peptide from the Indian leech. J Biol Chem 1993; 268: 8590-8595.
- 39 Richardson JL. et al. Crystal structure of the human alpha-thrombin-haemadin complex: an exosite II-binding inhibitor. EMBO J 2000; 19: 5650-5660.
- 40 Richardson JL. et al. Characterization of the residues involved in the human alpha-thrombin-haemadin complex: an exosite II-binding inhibitor. Biochemistry 2002; 41: 2535-2542.
- 41 Huntington JA. Molecular recognition mechanisms of thrombin. J Thromb Haemost 2005; 03: 1861-1872.
- 42 Laskowski M, Jr. Kato I. Protein inhibitors of proteinases. Annu Rev Biochem 1980; 49: 593-626.
- 43 Bode W, Huber R. Natural protein proteinase inhibitors and their interaction with proteinases. Eur J Biochem 1992; 204: 433-451.
- 44 Mans BJ. et al. Evolution of hematophagy in ticks: common origins for blood coagulation and platelet aggregation inhibitors from soft ticks of the genus Ornithodoros. Mol Biol Evol 2002; 19: 1695-1705.
- 45 Lai R. et al. A thrombin inhibitor from the ixodid tick, Amblyomma hebraeum . Gene 2004; 342: 243-249.
- 46 Macedo-Ribeiro S. et al. Isolation, cloning and structural characterisation of boophilin, a multifunctional Kunitz-type proteinase inhibitor from the cattle tick. PLoS ONE 2008; 03: e1624.
- 47 Liao M. et al. Hemalin, a thrombin inhibitor isolated from a midgut cDNA library from the hard tick Haemaphysalis longicornis . J Insect Physiol 2009; 55: 164-173.
- 48 van de Locht A. et al. The ornithodorin-thrombin crystal structure, a key to the TAP enigma?. EMBO J 1996; 15: 6011-6017.
- 49 Nienaber J. et al. Savignin, a potent thrombin inhibitor isolated from the salivary glands of the tick Ornithodoros savignyi (Acari: Argasidae). Exp Parasitol 1999; 93: 82-91.
- 50 Mans BJ. et al. Amino acid sequence and structure modeling of savignin, a thrombin inhibitor from the tick, Ornithodoros savignyi . Insect Biochem Mol Biol 2002; 32: 821-828.
- 51 Mans BJ. et al. Characterization of anti-hemostatic factors in the argasid, Argas monolakensis: Implications for the evolution of blood-feeding in the soft tick family. Insect Biochem Mol Biol 2008; 38: 22-41.
- 52 Friedrich T. et al. A Kazal-type inhibitor with thrombin specificity from Rhodnius prolixus . J Biol Chem 1993; 268: 16216-16222.
- 53 van de Locht A. et al. Two heads are better than one: crystal structure of the insect derived double domain Kazal inhibitor rhodniin in complex with thrombin. EMBO J 1995; 14: 5149-5157.
- 54 Mende K. et al. Dipetalogastin, a potent thrombin inhibitor from the blood-sucking insect. Dipetalogaster maximus cDNA cloning, expression and characterization. Eur J Biochem 1999; 266: 583-590.
- 55 Campos IT. et al. Infestin, a thrombin inhibitor presents in Triatoma infestans midgut, a Chagas’ disease vector: gene cloning, expression and characterization of the inhibitor. Insect Biochem Mol Biol 2002; 32: 991-997.
- 56 Lovato DV. et al. The full-length cDNA of anticoagulant protein infestin revealed a novel releasable Kazal domain, a neutrophil elastase inhibitor lacking anticoagulant activity. Biochimie 2006; 88: 673-681.
- 57 Campos IT. et al. Identification and characterization of a novel factor XIIa inhibitor in the hematophagous insect, Triatoma infestans (Hemiptera: Reduviidae). FEBS Lett 2004; 577: 512-516.
- 58 Flower DR. The lipocalin protein family: structure and function. Biochem J 1996; 318: 1-14.
- 59 Noeske-Jungblut C. et al. Triabin, a highly potent exosite inhibitor of thrombin. J Biol Chem 1995; 270: 28629-28634.
- 60 Fuentes-Prior P. et al. Structure of the thrombin complex with triabin, a lipocalin-like exosite-binding inhibitor derived from a triatomine bug. Proc Natl Acad Sci USA 1997; 94: 11845-11850.
- 61 Valenzuela JG. et al. Purification, cloning, and synthesis of a novel salivary anti-thrombin from the mosquito Anopheles albimanus . Biochemistry 1999; 38: 11209-11215.
- 62 Francischetti IM. et al. Anophelin: kinetics and mechanism of thrombin inhibition. Biochemistry 1999; 38: 16678-16685.
- 63 Zhang D. et al. Thrombostasin: purification, molecular cloning and expression of a novel anti-thrombin protein from horn fly saliva. Insect Biochem Mol Biol 2002; 32: 321-330.
- 64 Iwanaga S. et al. Identification and characterization of novel salivary thrombin inhibitors from the ixodidae tick, Haemaphysalis longicornis . Eur J Biochem 2003; 270: 1926-1934.
- 65 Nakajima C. et al. A novel gene encoding a thrombin inhibitory protein in a cDNA library from Haemaphysalis longicornis salivary gland. J Vet Med Sci 2006; 68: 447-452.
- 66 Nutt E. et al. The amino acid sequence of antistasin. A potent inhibitor of factor Xa reveals a repeated internal structure. J Biol Chem 1988; 263: 10162-10167.
- 67 Tuszynski GP. et al. Isolation and characterization of antistasin. An inhibitor of metastasis and coagulation. J Biol Chem 1987; 262: 9718-9723.
- 68 Salzet M. et al. Theromin, a novel leech thrombin inhibitor. J Biol Chem 2000; 275: 30774-30780.
- 69 Koh CY. et al. Variegin, a novel fast and tight binding thrombin inhibitor from the tropical bont tick. J Biol Chem 2007; 282: 29101-29113.
- 70 Waxman L. et al. Tick anticoagulant peptide (TAP) is a novel inhibitor of blood coagulation factor Xa. Science 1990; 248: 593-596.
- 71 Gaspar AR. et al. Isolation and characterization of an anticoagulant from the salivary glands of the tick, Ornithodoros savignyi (Acari: Argasidae). Exp Appl Acarol 1996; 20: 583-598.
- 72 Neeper MP. et al. Characterization of recombinant tick anticoagulant peptide. A highly selective inhibitor of blood coagulation factor Xa. J Biol Chem 1990; 265: 17746-17752.
- 73 Wei A. et al. Unexpected binding mode of tick anticoagulant peptide complexed to bovine factor Xa. J Mol Biol 1998; 283: 147-154.
- 74 Grutter MG. Proteinase inhibitors: another new fold. Structure 1994; 02: 575-576.
- 75 Cappello M. et al. Ancylostoma caninum anticoagulant peptide: a hookworm-derived inhibitor of human coagulation factor Xa. Proc Natl Acad Sci USA 1995; 92: 6152-6156.
- 76 Mieszczanek J. et al. Anticoagulant peptides from Ancylostoma caninum are immunologically distinct and localize to separate structures within the adult hookworm. Mol Biochem Parasitol 2004; 133: 319-323.
- 77 Stassens P. et al. Anticoagulant repertoire of the hookworm Ancylostoma caninum . Proc Natl Acad Sci U S A 1996; 93: 2149-2154.
- 78 Harrison LM. et al. Molecular characterization of Ancylostoma inhibitors of coagulation factor Xa. Hookworm anticoagulant activity in vitro predicts parasite bloodfeeding in vivo. J Biol Chem 2002; 277: 6223-6229.
- 79 Murakami MT. et al. Intermolecular interactions and characterization of the novel factor Xa exosite involved in macromolecular recognition and inhibition: crystal structure of human Gla-domainless factor Xa complexed with the anticoagulant protein NAPc2 from the hematophagous nematode Ancylostoma caninum . J Mol Biol 2007; 366: 602-610.
- 80 Rios-Steiner JL. et al. Active and exo-site inhibition of human factor Xa: structure of des-Gla factor Xa inhibited by NAP5, a potent nematode anticoagulant protein from Ancylostoma caninum . J Mol Biol 2007; 371: 774-786.
- 81 Mieszczanek J. et al. Ancylostoma ceylanicum anticoagulant peptide-1: role of the predicted reactive site amino acid in mediating inhibition of coagulation factors Xa and VIIa. Mol Biochem Parasitol 2004; 137: 151-159.
- 82 Brankamp RG. et al. Ghilantens: anticoagulantantimetastatic proteins from the South American leech, Haementeria ghilianii . J Lab Clin Med 1990; 115: 89-97.
- 83 Chopin V. et al. Therostasin, a novel clotting factor Xa inhibitor from the rhynchobdellid leech, Theromyzon tessulatum . J Biol Chem 2000; 275: 32701-32707.
- 84 Dunwiddie C. et al. Antistasin, a leech-derived inhibitor of factor Xa. Kinetic analysis of enzyme inhibition and identification of the reactive site. J Biol Chem 1989; 264: 16694-16699.
- 85 Lapatto R. et al. X-ray structure of antistasin at 1.9 A resolution and its modelled complex with blood coagulation factor Xa. EMBO J 1997; 16: 5151-5161.
- 86 Otlewski J. et al. The many faces of protease-protein inhibitor interaction. EMBO J 2005; 24: 1303-1310.
- 87 Stark KR, James AA. A factor Xa-directed anticoagulant from the salivary glands of the yellow fever mosquito Aedes aegypti . Exp Parasitol 1995; 81: 321-331.
- 88 Stark KR, James AA. Isolation and characterization of the gene encoding a novel factor Xa-directed anticoagulant from the yellow fever mosquito, Aedes aegypti . J Biol Chem 1998; 273: 20802-20809.
- 89 Joubert AM. et al. Isolation and characterization of an anticoagulant present in the salivary glands of the bont-legged tick, Hyalomma truncatum . Exp Appl Acarol 1995; 19: 79-92.
- 90 Ibrahim MA. et al. Factor Xa (FXa) inhibitor from the nymphs of the camel tick Hyalomma dromedarii. Comp Biochem Physiol B Biochem Mol Biol 2001; 130: 501-512.
- 91 Crawley JT, Lane DA. The haemostatic role of tissue factor pathway inhibitor. Arterioscler Thromb Vasc Biol 2008; 28: 233-242.
- 92 Francischetti IM. et al. Ixolaris, a novel recombinant tissue factor pathway inhibitor (TFPI) from the salivary gland of the tick, Ixodes scapularis: identification of factor X and factor Xa as scaffolds for the inhibition of factor VIIa/tissue factor complex. Blood 2002; 99: 3602-3612.
- 93 Monteiro RQ. et al. Ixolaris binding to factor X reveals a precursor state of factor Xa heparin-binding exosite. Protein Sci 2008; 17: 146-153.
- 94 Monteiro RQ. et al. Ixolaris: a factor Xa heparinbinding exosite inhibitor. Biochem J 2005; 387: 871-877.
- 95 Francischetti IM. et al. Penthalaris, a novel recombinant five-Kunitz tissue factor pathway inhibitor (TFPI) from the salivary gland of the tick vector of Lyme disease, Ixodes scapularis . Thromb Haemost 2004; 91: 886-898.
- 96 Buddai SK. et al. Nematode anticoagulant protein c2 reveals a site on factor Xa that is important for macromolecular substrate binding to human prothrombinase. J Biol Chem 2002; 277: 26689-26698.
- 97 Duggan BM. et al. Inherent flexibility in a potent inhibitor of blood coagulation, recombinant nematode anticoagulant protein c2. Eur J Biochem 1999; 265: 539-548.
- 98 Rezaie AR. Identification of basic residues in the heparin-binding exosite of factor Xa critical for heparin and factor Va binding. J Biol Chem 2000; 275: 3320-3327.
- 99 Giugliano RP. et al. Recombinant nematode anticoagulant protein c2 in patients with non-ST-segment elevation acute coronary syndrome: the ANTHEMTIMI-32 trial. J Am Coll Cardiol 2007; 49: 2398-2407.
- 100 Ledizet M. et al. Discovery and pre-clinical development of antithrombotics from hematophagous invertebrates. Curr Med Chem Cardiovasc Hematol Agents 2005; 03: 1-10.
- 101 Ribeiro JM. et al. Purification and characterization of prolixin S (nitrophorin 2), the salivary anticoagulant of the blood-sucking bug Rhodnius prolixus. Biochem J 1995; 308 (01) 243-249.
- 102 Isawa H. et al. The insect salivary protein, prolixin-S, inhibits factor IXa generation and Xase complex formation in the blood coagulation pathway. J Biol Chem 2000; 275: 6636-6641.
- 103 Zhang Y. et al. Nitrophorin-2: a novel mixed-type reversible specific inhibitor of the intrinsic factor-X activating complex. Biochemistry 1998; 37: 10681-10690.
- 104 Andersen JF, Montfort WR. The crystal structure of nitrophorin 2. A trifunctional antihemostatic protein from the saliva of Rhodnius prolixus. J Biol Chem 2000; 275: 30496-30503.
- 105 Kato N. et al. Identification and characterization of the plasma kallikrein-kinin system inhibitor, haemaphysalin, from hard tick, Haemaphysalis longicornis. Thromb Haemost 2005; 93: 359-367.
- 106 Isawa H. et al. A mosquito salivary protein inhibits activation of the plasma contact system by binding to factor XII and high molecular weight kininogen. J Biol Chem 2002; 277: 27651-27658.
- 107 Tanaka AS. et al. A double headed serine proteinase inhibitor--human plasma kallikrein and elastase inhibitor--from Boophilus microplus larvae. Immunopharmacology 1999; 45: 171-177.
- 108 Sasaki SD. et al. Boophilus microplus tick larvae, a rich source of Kunitz type serine proteinase inhibitors. Biochimie 2004; 86: 643-649.
- 109 Sant’Anna AS. et al. Rhipicephalus sanguineus trypsin inhibitors present in the tick larvae: isolation, characterization, and partial primary structure determination. Arch Biochem Biophys 2003; 417: 176-182.
- 110 Yang L. et al. Heparin-activated antithrombin interacts with the autolysis loop of target coagulation proteases. Blood 2004; 104: 1753-1759.
- 111 Ciprandi A. et al. Boophilus microplus: its saliva contains microphilin, a small thrombin inhibitor. Exp Parasitol 2006; 114: 40-46.
- 112 Horn F. et al. Boophilus microplus anticoagulant protein: an antithrombin inhibitor isolated from the cattle tick saliva. Arch Biochem Biophys 2000; 384: 68-73.
- 113 Ricci CG. et al. A thrombin inhibitor from the gut of Boophilus microplus ticks. Exp Appl Acarol 2007; 42: 291-300.
- 114 Electricwala A. et al. Isolation of thrombin inhibitor from the leech Hirudinaria manillensis. Blood Coagul Fibrinolysis 1991; 02: 83-89.
- 115 Bock PE. et al. Exosites in the substrate specificity of blood coagulation reactions. J Thromb Haemost 2007; 05 (Suppl. 01) 81-94.
- 116 Maraganore JM. et al. Design and characterization of hirulogs: a novel class of bivalent peptide inhibitors of thrombin. Biochemistry 1990; 29: 7095-7101.
- 117 Hong SJ, Kang KW. Purification of granulin-like polypeptide from the blood-sucking leech, Hirudo nipponia. Protein Expr Purif 1999; 16: 340-346.
- 118 Cappello M. et al. Tsetse thrombin inhibitor: bloodmeal-induced expression of an anticoagulant in salivary glands and gut tissue of Glossina morsitans morsitans. Proc Natl Acad Sci U S A 1998; 95: 14290-14295.
- 119 Ibrahim MA. et al. Isolation and properties of two forms of thrombin inhibitor from the nymphs of the camel tick Hyalomma dromedarii (Acari: Ixodidae). Exp Appl Acarol 2001; 25: 675-698.
- 120 Zhu K. et al. Isolation and characterization of americanin, a specific inhibitor of thrombin, from the salivary glands of the lone star tick Amblyomma americanum (L.). Exp Parasitol 1997; 87: 30-38.
- 121 Motoyashiki T. et al. Isolation of anticoagulant from the venom of tick, Boophilus calcaratus, from Uzbekistan. Thromb Res 2003; 110: 235-241.
- 122 Waidhet-Kouadio P. et al. Purification and characterization of a thrombin inhibitor from the salivary glands of a malarial vector mosquito, Anopheles stephensi. Biochim Biophys Acta 1998; 1381: 227-233.
- 123 Arocha-Pinango CL. et al. Inventory of exogenous hemostatic factors derived form arthropods. Registry of Exogenous Hemostatic Factors of the Scientific and Standardization Subcommittee of the International Society on Thrombosis and Haemostasis. Thromb Haemost 1999; 81: 647-656.
- 124 Abebe M. et al. Simulidin: a black fly (Simulium vittatum) salivary gland protein with anti-thrombin activity. J Insect Physiol 2008; 41: 1001-1006.
- 125 Kazimirova M. et al. Anticoagulant activities in salivary glands of tabanid flies. Med Vet Entomol 2002; 16: 301-309.
- 126 Stark KR, James AA. Salivary gland anticoagulants in culicine and anopheline mosquitoes (Diptera:Culicidae). J Med Entomol 1996; 33: 645-650.
- 127 Abebe M. et al. Anticoagulant activity in salivary gland extracts of black flies (Diptera: Simuliidae). J Med Entomol 1994; 31: 908-11.
- 128 Pereira MH. et al. Anticoagulant activity of Triatoma infestans and Panstrongylus megistus saliva (Hemiptera/Triatominae). Acta Trop 1996; 61: 255-261.
- 129 Narasimhan S. et al. A novel family of anticoagulants from the saliva of Ixodes scapularis. Insect Mol Biol 2002; 11: 641-650.
- 130 Faria F. et al. A new factor Xa inhibitor (lefaxin) from the Haementeria depressa leech. Thromb Haemost 1999; 82: 1469-1473.
- 131 Fernandez AZ. et al. Draculin, the anticoagulant factor in vampire bat saliva, is a tight-binding, noncompetitive inhibitor of activated factor X. Biochim Biophys Acta 1999; 1434: 135-142.
- 132 Zhu K. et al. Identification and characterization of anticoagulant activities in the saliva of the lone star tick, Amblyomma americanum (L.). J Parasitol 1997; 83: 38-43.
- 133 Perez de Leon AA. et al. Anticoagulant activity in salivary glands of the insect vector Culicoides variipennis sonorensis by an inhibitor of factor Xa. Exp Parasitol 1998; 88: 121-130.
- 134 Jacobs JW. et al. Isolation and characterization of a coagulation factor Xa inhibitor from black fly salivary glands. Thromb Haemost 1990; 64: 235-238.
- 135 Condra C. et al. Isolation and structural characterization of a potent inhibitor of coagulation factor Xa from the leech Haementeria ghilianii. Thromb Haemost 1989; 61: 437-441.
- 136 Abebe M. et al. Novel anticoagulant from salivary glands of Simulium vittatum (Diptera: Simuliidae) inhibits activity of coagulation factor V. J Med Entomol 1996; 33: 173-176.
- 137 Gordon JR, Allen JR. Factors V and VII anticoagulant activities in the salivary glands of feeding Dermacentor andersoni ticks. J Parasitol 1991; 77: 167-170.
- 138 Limo MK. et al. Purification and characterization of an anticoagulant from the salivary glands of the ixodid tick Rhipicephalus appendiculatus. Exp Parasitol 1991; 72: 418-429.
- 139 Kim DR, Kang KW. Amino acid sequence of piguamerin, an antistasin-type protease inhibitor from the blood sucking leech Hirudo nipponia. Eur J Biochem 1998; 254: 692-697.