title: Characterization of the receptor-destroying enzyme activity from infectious salmon anaemia virus.
abstract: Infectious salmon anaemia virus (ISAV) infects cells via the endocytic pathway and, like many other enveloped viruses, ISAV contains a receptor-destroying enzyme. We have analysed this acetylesterase activity with respect to substrate specificity, enzyme kinetics, inhibitors, temperature and pH stability. The ISAV acetylesterase was inhibited by di-isopropyl fluorophosphate (DFP) in a dose-dependent fashion but not by other known hydrolase inhibitors, suggesting that a serine residue is part of the active site. The pH optimum of the enzyme was in the range 7.5-8.0 and the enzymatic activity was lessened at temperatures above 40 degrees C. The effect of DFP on agglutination/elution of erythrocytes by ISAV demonstrated that the acetylesterase activity is the bona fide receptor-destroying enzyme. A haemadsorption assay was used to analyse whether the esterase was active on the surface of infected cells or not.
authors.affiliation: Department of Microbiology, School of Pharmacy, PO Box 1068, Blindern, 0316 Oslo, Norway1.
authors.forename: Marianne
authors.initials: M
authors.lastname: Kristiansen
authors.affiliation: Department of Microbiology, School of Pharmacy, PO Box 1068, Blindern, 0316 Oslo, Norway1.
authors.forename: Marianne K
authors.initials: MK
authors.lastname: Frøystad
authors.affiliation: Department of Microbiology, School of Pharmacy, PO Box 1068, Blindern, 0316 Oslo, Norway1.
authors.forename: Anne Lise
authors.initials: AL
authors.lastname: Rishovd
authors.affiliation: Department of Microbiology, School of Pharmacy, PO Box 1068, Blindern, 0316 Oslo, Norway1.
authors.forename: Tor
authors.initials: T
authors.lastname: Gjøen
mesh_terms: D000115:Acetylesterase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000372:Agglutination Tests; D000818:Animals; D002460:Cell Line; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004912:Erythrocytes; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007531:Isoflurophate / Q000494:pharmacology; D007700:Kinetics; D009975:Orthomyxoviridae / Q000201:enzymology*; D011991:Receptors, Virus / Q000378:metabolism*; D020317:Salmo salar; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D004791:Enzyme Inhibitors; D011991:Receptors, Virus; D007531:Isoflurophate; D000115:Acetylesterase