title: Purification and characterization of an anticoagulant from the salivary glands of the ixodid tick Rhipicephalus appendiculatus.
abstract: An anticoagulant isolated from salivary gland extracts of the ixodid tick Rhipicephalus appendiculatus was purified by gel filtration on Sephadex G-100, ion exchange on DEAE-cellulose, aprotinin-Sepharose, and by high-pressure-liquid size-exclusion chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the anticoagulant activity was associated with a protein of an apparent Mr of 65 kDa. The purified molecule had a pI in the range of 8.0-8.5 on chromatofocusing and was stable over a wide pH range, but was heat labile and susceptible to inactivation by trypsin and reductive alkylation. The anticoagulant did not inhibit thrombin-initiated fibrin formation and had no detectable fibrino(geno)lytic or phospholipase-like activities. Although it inhibited factor Xa-induced clotting of bovine plasma, it did not affect the amidase activity of factor Xa toward a synthetic substrate, suggesting that the anticoagulant acts at a site distinct from the active site of factor Xa or on other components of the prothrombinase complex.
authors.affiliation: Department of Veterinary Microbiology and Immunology, University of California, Davis 95616.
authors.forename: M K
authors.initials: MK
authors.lastname: Limo
authors.forename: W P
authors.initials: WP
authors.lastname: Voigt
authors.forename: A G
authors.initials: AG
authors.lastname: Tumbo-Oeri
authors.forename: R M
authors.initials: RM
authors.lastname: Njogu
authors.forename: O K
authors.initials: OK
authors.lastname: ole-MoiYoi
mesh_terms: D000818:Animals; D001777:Blood Coagulation; D002851:Chromatography, High Pressure Liquid; D005165:Factor V / Q000037:antagonists & inhibitors*; D005170:Factor X / Q000037:antagonists & inhibitors*; D015951:Factor Xa; D065427:Factor Xa Inhibitors; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D008970:Molecular Weight; D009842:Oligopeptides / Q000378:metabolism; D011506:Proteins / Q000302:isolation & purification* / Q000378:metabolism / Q000494:pharmacology; D012469:Salivary Glands / Q000737:chemistry; D013696:Temperature; D013987:Ticks / Q000032:analysis*
chemical_list: D065427:Factor Xa Inhibitors; D009842:Oligopeptides; D011506:Proteins; C022475:prothrombinase complex; C015608:benzoyl-Ile-Glu-Gly-Arg-p-nitroanilide; D005165:Factor V; D005170:Factor X; D015951:Factor Xa