Peroxygenase and oxidase activities of dehaloperoxidase-hemoglobin from Amphitrite ornata.
In: Journal of the American Chemical Society, Jg. 136 (2014-06-04), Heft 22, S. 7914-25
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Zugriff:
The marine globin dehaloperoxidase-hemoglobin (DHP) from Amphitrite ornata was found to catalyze the H2O2-dependent oxidation of monohaloindoles, a previously unknown class of substrate for DHP. Using 5-Br-indole as a representative substrate, the major monooxygenated products were found to be 5-Br-2-oxindole and 5-Br-3-oxindolenine. Isotope labeling studies confirmed that the oxygen atom incorporated was derived exclusively from H2O2, indicative of a previously unreported peroxygenase activity for DHP. Peroxygenase activity could be initiated from either the ferric or oxyferrous states with equivalent substrate conversion and product distribution. It was found that 5-Br-3-oxindole, a precursor of the product 5-Br-3-oxindolenine, readily reduced the ferric enzyme to the oxyferrous state, demonstrating an unusual product-driven reduction of the enzyme. As such, DHP returns to the globin-active oxyferrous form after peroxygenase activity ceases. Reactivity with 5-Br-3-oxindole in the absence of H2O2 also yielded 5,5'-Br2-indigo above the expected reaction stoichiometry under aerobic conditions, and O2-concentration studies demonstrated dioxygen consumption. Nonenzymatic and anaerobic controls both confirmed the requirements for DHP and molecular oxygen in the catalytic generation of 5,5'-Br2-indigo, and together suggest a newly identified oxidase activity for DHP.
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Peroxygenase and oxidase activities of dehaloperoxidase-hemoglobin from Amphitrite ornata.
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Autor/in / Beteiligte Person: | Barrios, DA ; D'Antonio, J ; McCombs, NL ; Zhao, J ; Franzen, S ; Schmidt, AC ; Sombers, LA ; Ghiladi, RA |
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Zeitschrift: | Journal of the American Chemical Society, Jg. 136 (2014-06-04), Heft 22, S. 7914-25 |
Veröffentlichung: | Washington, DC : American Chemical Society ; <i>Original Publication</i>: Easton, Pa. [etc.], 2014 |
Medientyp: | academicJournal |
ISSN: | 1520-5126 (electronic) |
DOI: | 10.1021/ja500293c |
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