Oxidizing substrate specificity of Mycobacterium tuberculosis alkyl hydroperoxide reductase E: Kinetics and mechanisms of oxidation and overoxidation
Alkyl hydroperoxide reductase E (AhpE), a novel subgroup of the peroxiredoxin family, comprises Mycobacterium tuberculosis AhpE (MtAhpE) and AhpE-like proteins present in many bacteria and archaea, for which functional characterization is scarce. We previously reported that MtAhpE reacted ~ 10 3 tim...
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todo:paper_08915849_v51_n2_p464_Reyes2023-10-03T15:41:21Z Oxidizing substrate specificity of Mycobacterium tuberculosis alkyl hydroperoxide reductase E: Kinetics and mechanisms of oxidation and overoxidation Reyes, A.M. Hugo, M. Trostchansky, A. Capece, L. Radi, R. Trujillo, M. Alkyl hydroperoxide reductase E Arachidonic acid Free radicals Hydroperoxide Mycobacterium tuberculosis Peroxidase Peroxiredoxin alcohol alkyl hydroperoxide reductase E arachidonic acid hydroperoxide peroxiredoxin sulfenic acid derivative thiol unclassified drug article enzyme inactivation enzyme specificity hydrophobicity kinetics Mycobacterium tuberculosis nonhuman oxidation priority journal proton transport stoichiometry Chromatography, Liquid Kinetics Mycobacterium tuberculosis Oxidation-Reduction Peroxiredoxins Substrate Specificity Tandem Mass Spectrometry Mycobacterium tuberculosis Alkyl hydroperoxide reductase E (AhpE), a novel subgroup of the peroxiredoxin family, comprises Mycobacterium tuberculosis AhpE (MtAhpE) and AhpE-like proteins present in many bacteria and archaea, for which functional characterization is scarce. We previously reported that MtAhpE reacted ~ 10 3 times faster with peroxynitrite than with hydrogen peroxide, but the molecular reasons for that remained unknown. Herein, we investigated the oxidizing substrate specificity and the oxidative inactivation of the enzyme. In most cases, both peroxidatic thiol oxidation and sulfenic acid overoxidation followed a trend in which those peroxides with the lower leaving-group pK a reacted faster than others. These data are in agreement with the accepted mechanisms of thiol oxidation and support that overoxidation occurs through sulfenate anion reaction with the protonated peroxide. However, MtAhpE oxidation and overoxidation by fatty acid-derived hydroperoxides (~ 10 8 and 10 5 M - 1 s - 1, respectively, at pH 7.4 and 25 °C) were much faster than expected according to the Brønsted relationship with leaving-group pK a. A stoichiometric reduction of the arachidonic acid hydroperoxide 15-HpETE to its corresponding alcohol was confirmed. Interactions of fatty acid hydroperoxides with a hydrophobic groove present on the reduced MtAhpE surface could be the basis of their surprisingly fast reactivity. © 2011 Elsevier Inc. Fil:Capece, L. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_08915849_v51_n2_p464_Reyes |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Alkyl hydroperoxide reductase E Arachidonic acid Free radicals Hydroperoxide Mycobacterium tuberculosis Peroxidase Peroxiredoxin alcohol alkyl hydroperoxide reductase E arachidonic acid hydroperoxide peroxiredoxin sulfenic acid derivative thiol unclassified drug article enzyme inactivation enzyme specificity hydrophobicity kinetics Mycobacterium tuberculosis nonhuman oxidation priority journal proton transport stoichiometry Chromatography, Liquid Kinetics Mycobacterium tuberculosis Oxidation-Reduction Peroxiredoxins Substrate Specificity Tandem Mass Spectrometry Mycobacterium tuberculosis |
| spellingShingle |
Alkyl hydroperoxide reductase E Arachidonic acid Free radicals Hydroperoxide Mycobacterium tuberculosis Peroxidase Peroxiredoxin alcohol alkyl hydroperoxide reductase E arachidonic acid hydroperoxide peroxiredoxin sulfenic acid derivative thiol unclassified drug article enzyme inactivation enzyme specificity hydrophobicity kinetics Mycobacterium tuberculosis nonhuman oxidation priority journal proton transport stoichiometry Chromatography, Liquid Kinetics Mycobacterium tuberculosis Oxidation-Reduction Peroxiredoxins Substrate Specificity Tandem Mass Spectrometry Mycobacterium tuberculosis Reyes, A.M. Hugo, M. Trostchansky, A. Capece, L. Radi, R. Trujillo, M. Oxidizing substrate specificity of Mycobacterium tuberculosis alkyl hydroperoxide reductase E: Kinetics and mechanisms of oxidation and overoxidation |
| topic_facet |
Alkyl hydroperoxide reductase E Arachidonic acid Free radicals Hydroperoxide Mycobacterium tuberculosis Peroxidase Peroxiredoxin alcohol alkyl hydroperoxide reductase E arachidonic acid hydroperoxide peroxiredoxin sulfenic acid derivative thiol unclassified drug article enzyme inactivation enzyme specificity hydrophobicity kinetics Mycobacterium tuberculosis nonhuman oxidation priority journal proton transport stoichiometry Chromatography, Liquid Kinetics Mycobacterium tuberculosis Oxidation-Reduction Peroxiredoxins Substrate Specificity Tandem Mass Spectrometry Mycobacterium tuberculosis |
| description |
Alkyl hydroperoxide reductase E (AhpE), a novel subgroup of the peroxiredoxin family, comprises Mycobacterium tuberculosis AhpE (MtAhpE) and AhpE-like proteins present in many bacteria and archaea, for which functional characterization is scarce. We previously reported that MtAhpE reacted ~ 10 3 times faster with peroxynitrite than with hydrogen peroxide, but the molecular reasons for that remained unknown. Herein, we investigated the oxidizing substrate specificity and the oxidative inactivation of the enzyme. In most cases, both peroxidatic thiol oxidation and sulfenic acid overoxidation followed a trend in which those peroxides with the lower leaving-group pK a reacted faster than others. These data are in agreement with the accepted mechanisms of thiol oxidation and support that overoxidation occurs through sulfenate anion reaction with the protonated peroxide. However, MtAhpE oxidation and overoxidation by fatty acid-derived hydroperoxides (~ 10 8 and 10 5 M - 1 s - 1, respectively, at pH 7.4 and 25 °C) were much faster than expected according to the Brønsted relationship with leaving-group pK a. A stoichiometric reduction of the arachidonic acid hydroperoxide 15-HpETE to its corresponding alcohol was confirmed. Interactions of fatty acid hydroperoxides with a hydrophobic groove present on the reduced MtAhpE surface could be the basis of their surprisingly fast reactivity. © 2011 Elsevier Inc. |
| format |
JOUR |
| author |
Reyes, A.M. Hugo, M. Trostchansky, A. Capece, L. Radi, R. Trujillo, M. |
| author_facet |
Reyes, A.M. Hugo, M. Trostchansky, A. Capece, L. Radi, R. Trujillo, M. |
| author_sort |
Reyes, A.M. |
| title |
Oxidizing substrate specificity of Mycobacterium tuberculosis alkyl hydroperoxide reductase E: Kinetics and mechanisms of oxidation and overoxidation |
| title_short |
Oxidizing substrate specificity of Mycobacterium tuberculosis alkyl hydroperoxide reductase E: Kinetics and mechanisms of oxidation and overoxidation |
| title_full |
Oxidizing substrate specificity of Mycobacterium tuberculosis alkyl hydroperoxide reductase E: Kinetics and mechanisms of oxidation and overoxidation |
| title_fullStr |
Oxidizing substrate specificity of Mycobacterium tuberculosis alkyl hydroperoxide reductase E: Kinetics and mechanisms of oxidation and overoxidation |
| title_full_unstemmed |
Oxidizing substrate specificity of Mycobacterium tuberculosis alkyl hydroperoxide reductase E: Kinetics and mechanisms of oxidation and overoxidation |
| title_sort |
oxidizing substrate specificity of mycobacterium tuberculosis alkyl hydroperoxide reductase e: kinetics and mechanisms of oxidation and overoxidation |
| url |
http://hdl.handle.net/20.500.12110/paper_08915849_v51_n2_p464_Reyes |
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