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Reversible Oxidative Modifications in Myoglobin and Functional Implications
Myoglobin (Mb), an oxygen-binding heme protein highly expressed in heart and skeletal muscle, has been shown to undergo oxidative modifications on both an inter- and intramolecular level when exposed to hydrogen peroxide (H(2)O(2)) in vitro. Here, we show that exposure to H(2)O(2) increases the pero...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7346209/ https://www.ncbi.nlm.nih.gov/pubmed/32599765 http://dx.doi.org/10.3390/antiox9060549 |
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author | Mannino, Mark H. Patel, Rishi S. Eccardt, Amanda M. Janowiak, Blythe E. Wood, David C. He, Fahu Fisher, Jonathan S. |
author_facet | Mannino, Mark H. Patel, Rishi S. Eccardt, Amanda M. Janowiak, Blythe E. Wood, David C. He, Fahu Fisher, Jonathan S. |
author_sort | Mannino, Mark H. |
collection | PubMed |
description | Myoglobin (Mb), an oxygen-binding heme protein highly expressed in heart and skeletal muscle, has been shown to undergo oxidative modifications on both an inter- and intramolecular level when exposed to hydrogen peroxide (H(2)O(2)) in vitro. Here, we show that exposure to H(2)O(2) increases the peroxidase activity of Mb. Reaction of Mb with H(2)O(2) causes covalent binding of heme to the Mb protein (Mb-X), corresponding to an increase in peroxidase activity when ascorbic acid is the reducing co-substrate. Treatment of H(2)O(2)-reacted Mb with ascorbic acid reverses the Mb-X crosslink. Reaction with H(2)O(2) causes Mb to form dimers, trimers, and larger molecular weight Mb aggregates, and treatment with ascorbic acid regenerates Mb monomers. Reaction of Mb with H(2)O(2) causes formation of dityrosine crosslinks, though the labile nature of the crosslinks broken by treatment with ascorbic acid suggests that the reversible aggregation of Mb is mediated by crosslinks other than dityrosine. Disappearance of a peptide containing a tryptophan residue when Mb is treated with H(2)O(2) and the peptide’s reappearance after subsequent treatment with ascorbic acid suggest that tryptophan side chains might participate in the labile crosslinking. Taken together, these data suggest that while exposure to H(2)O(2) causes Mb-X formation, increases Mb peroxidase activity, and causes Mb aggregation, these oxidative modifications are reversible by treatment with ascorbic acid. A caveat is that future studies should demonstrate that these and other in vitro findings regarding properties of Mb have relevance in the intracellular milieu, especially in regard to actual concentrations of metMb, H(2)O(2), and ascorbate that would be found in vivo. |
format | Online Article Text |
id | pubmed-7346209 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-73462092020-07-20 Reversible Oxidative Modifications in Myoglobin and Functional Implications Mannino, Mark H. Patel, Rishi S. Eccardt, Amanda M. Janowiak, Blythe E. Wood, David C. He, Fahu Fisher, Jonathan S. Antioxidants (Basel) Article Myoglobin (Mb), an oxygen-binding heme protein highly expressed in heart and skeletal muscle, has been shown to undergo oxidative modifications on both an inter- and intramolecular level when exposed to hydrogen peroxide (H(2)O(2)) in vitro. Here, we show that exposure to H(2)O(2) increases the peroxidase activity of Mb. Reaction of Mb with H(2)O(2) causes covalent binding of heme to the Mb protein (Mb-X), corresponding to an increase in peroxidase activity when ascorbic acid is the reducing co-substrate. Treatment of H(2)O(2)-reacted Mb with ascorbic acid reverses the Mb-X crosslink. Reaction with H(2)O(2) causes Mb to form dimers, trimers, and larger molecular weight Mb aggregates, and treatment with ascorbic acid regenerates Mb monomers. Reaction of Mb with H(2)O(2) causes formation of dityrosine crosslinks, though the labile nature of the crosslinks broken by treatment with ascorbic acid suggests that the reversible aggregation of Mb is mediated by crosslinks other than dityrosine. Disappearance of a peptide containing a tryptophan residue when Mb is treated with H(2)O(2) and the peptide’s reappearance after subsequent treatment with ascorbic acid suggest that tryptophan side chains might participate in the labile crosslinking. Taken together, these data suggest that while exposure to H(2)O(2) causes Mb-X formation, increases Mb peroxidase activity, and causes Mb aggregation, these oxidative modifications are reversible by treatment with ascorbic acid. A caveat is that future studies should demonstrate that these and other in vitro findings regarding properties of Mb have relevance in the intracellular milieu, especially in regard to actual concentrations of metMb, H(2)O(2), and ascorbate that would be found in vivo. MDPI 2020-06-24 /pmc/articles/PMC7346209/ /pubmed/32599765 http://dx.doi.org/10.3390/antiox9060549 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Mannino, Mark H. Patel, Rishi S. Eccardt, Amanda M. Janowiak, Blythe E. Wood, David C. He, Fahu Fisher, Jonathan S. Reversible Oxidative Modifications in Myoglobin and Functional Implications |
title | Reversible Oxidative Modifications in Myoglobin and Functional Implications |
title_full | Reversible Oxidative Modifications in Myoglobin and Functional Implications |
title_fullStr | Reversible Oxidative Modifications in Myoglobin and Functional Implications |
title_full_unstemmed | Reversible Oxidative Modifications in Myoglobin and Functional Implications |
title_short | Reversible Oxidative Modifications in Myoglobin and Functional Implications |
title_sort | reversible oxidative modifications in myoglobin and functional implications |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7346209/ https://www.ncbi.nlm.nih.gov/pubmed/32599765 http://dx.doi.org/10.3390/antiox9060549 |
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