title: Biochemical characterisation of the recombinant peroxiredoxin (FhePrx) of the liver fluke, Fasciola hepatica.
abstract: The parasitic helminth Fasciola hepatica secretes a 2-Cys peroxiredoxin (Prx) that may play important functions in host-parasite interaction. Recombinant peroxiredoxin (FhePrx) prevented metal-catalyzed oxidative nicking of plasmid DNA and detoxified hydrogen peroxide when coupled with Escherichia coli thioredoxin and thioredoxin reductase (k(cat)/K(m)=5.2 x 10(5)M(-1)s(-1)). Enzyme kinetic analysis revealed that the catalytic efficiency of FhePrx is similar to other 2-Cys peroxiredoxins; the enzyme displayed saturable enzyme Michaelis-Menten type kinetics with hydrogen peroxide, cumene hydroperoxide and t-butyl hydroperoxide, and is sensitive to concentrations of hydrogen peroxide above 0.5 mM. Like the 2-Cys peroxiredoxins from a related helminth, Schistosoma mansoni, steady-state kinetics indicate that FhePrx exhibits a saturable, single displacement-like reaction mechanism rather than non-saturable double displacement (ping-pong) enzyme substitution mechanism common to other peroxiredoxins. However, unlike the schistosome Prxs, FhePrx could not utilise reducing equivalents supplied by glutathione or glutathione reductase.
authors.affiliation: School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland. Mary.Sekiya@ucd.ie
authors.forename: Mary
authors.initials: M
authors.lastname: Sekiya
authors.forename: Grace
authors.initials: G
authors.lastname: Mulcahy
authors.forename: Jane A
authors.initials: JA
authors.lastname: Irwin
authors.forename: Colin M
authors.initials: CM
authors.lastname: Stack
authors.forename: Sheila M
authors.initials: SM
authors.lastname: Donnelly
authors.forename: Weibo
authors.initials: W
authors.lastname: Xu
authors.forename: Peter
authors.initials: P
authors.lastname: Collins
authors.forename: John P
authors.initials: JP
authors.lastname: Dalton
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D005210:Fasciola hepatica / Q000201:enzymology* / Q000254:growth & development; D006861:Hydrogen Peroxide / Q000378:metabolism; D007700:Kinetics; D008018:Life Cycle Stages; D010544:Peroxidases / Q000302:isolation & purification / Q000378:metabolism*; D010957:Plasmids / Q000378:metabolism; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism*; D012756:Sheep
chemical_list: D000975:Antioxidants; D011994:Recombinant Proteins; D004247:DNA; D006861:Hydrogen Peroxide; D010544:Peroxidases