title: Enzyme function of the globin dehaloperoxidase from Amphitrite ornata is activated by substrate binding.
abstract: Amphitrite ornata dehaloperoxidase (DHP) is a heme enzyme with a globin structure, which is capable of oxidizing para-halogenated phenols to the corresponding quinones. Cloning, high-level expression, and purification of recombinant DHP are described. Recombinant DHP was assayed by stopped-flow experiments for its ability to oxidatively debrominate 2,4,6-tribromophenol (TBP). The enzymatic activity of the ferric form of recombinant DHP is intermediate between that of a typical peroxidase (horseradish peroxidase) and a typical globin (horse heart myoglobin). The present study shows that, unlike other known peroxidases, DHP activity requires the addition of substrate, TBP, prior to the cosubstrate, peroxide. The presence of a substrate-binding site in DHP is consistent with a two-electron oxidation mechanism and an obligatory order for activation of the enzyme by addition of the substrate prior to the cosubstrate.
authors.affiliation: Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Belyea
authors.forename: Lauren B
authors.initials: LB
authors.lastname: Gilvey
authors.forename: Michael F
authors.initials: MF
authors.lastname: Davis
authors.forename: Marisha
authors.initials: M
authors.lastname: Godek
authors.forename: Tim L
authors.initials: TL
authors.lastname: Sit
authors.forename: Steven A
authors.initials: SA
authors.lastname: Lommel
authors.forename: Stefan
authors.initials: S
authors.lastname: Franzen
mesh_terms: D000818:Animals; D003001:Cloning, Molecular; D004789:Enzyme Activation; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D005914:Globins / Q000378:metabolism; D006454:Hemoglobins; D006861:Hydrogen Peroxide / Q000378:metabolism; D010544:Peroxidases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010636:Phenols / Q000378:metabolism; D011077:Polychaeta / Q000201:enzymology; D011485:Protein Binding; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D006454:Hemoglobins; D010636:Phenols; D011994:Recombinant Proteins; D005914:Globins; D006861:Hydrogen Peroxide; C098661:DHP I dehaloperoxidase; D010544:Peroxidases; C004554:2,4,6-tribromophenol