title: Isolation and characterization of a trypsin-like enzyme from the buffalo fly, Haematobia irritans exigua.
abstract: The incorporation of soybean trypsin inhibitor (SBTI) into the diet of the buffalo fly, Haematobia irritans exigua (De Meijere), results in increased mortality and reduced fecundity. A trypsin-like enzyme which binds to SBTI was isolated by affinity chromatography on a Sepharose-SBTI column followed by ion-exchange chromatography. The enzyme was inhibited by benzamidine, phenylmethylsulfonyl fluoride, ovomucoid, leupeptin and alpha-2 macroglobulin. The enzyme was not inhibited by EDTA or p-chloromecuribenzoic acid and had a broad pH optimum of pH 7-9. Vaccination of sheep produced antibodies specific for the trypsin-like enzyme which inhibited enzyme activity in vitro but did not affect the survival of flies maintained in in vitro culture.
authors.affiliation: CSIRO Division of Tropical Animal Production, Long Pocket Laboratories, Indooroopilly, Queensland, Australia.
authors.forename: I J
authors.initials: IJ
authors.lastname: East
authors.forename: P G
authors.initials: PG
authors.lastname: Allingham
authors.forename: R J
authors.initials: RJ
authors.lastname: Bunch
authors.forename: J
authors.initials: J
authors.lastname: Matheson
mesh_terms: D000818:Animals; D002417:Cattle; D010450:Endopeptidases / Q000737:chemistry / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D009117:Muscidae / Q000201:enzymology* / Q000276:immunology; D012756:Sheep / Q000276:immunology; D014357:Trypsin / Q000737:chemistry; D014361:Trypsin Inhibitors / Q000494:pharmacology; D014611:Vaccination
chemical_list: D014361:Trypsin Inhibitors; D010450:Endopeptidases; D014357:Trypsin