Ascorbate oxidation by iron, copper and reactive oxygen species: review, model development, and derivation of key rate constants

Abstract Ascorbic acid is among the most abundant antioxidants in the lung, where it likely plays a key role in the mechanism by which particulate air pollution initiates a biological response. Because ascorbic acid is a highly redox active species, it engages in a far more complex web of reactions...

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Autores principales:	Jiaqi Shen, Paul T. Griffiths, Steven J. Campbell, Battist Utinger, Markus Kalberer, Suzanne E. Paulson
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2021
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/53a555c11cac48b0be1dacd8ef5ff865
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spelling	oai:doaj.org-article:53a555c11cac48b0be1dacd8ef5ff8652021-12-02T14:23:18ZAscorbate oxidation by iron, copper and reactive oxygen species: review, model development, and derivation of key rate constants10.1038/s41598-021-86477-82045-2322https://doaj.org/article/53a555c11cac48b0be1dacd8ef5ff8652021-04-01T00:00:00Zhttps://doi.org/10.1038/s41598-021-86477-8https://doaj.org/toc/2045-2322Abstract Ascorbic acid is among the most abundant antioxidants in the lung, where it likely plays a key role in the mechanism by which particulate air pollution initiates a biological response. Because ascorbic acid is a highly redox active species, it engages in a far more complex web of reactions than a typical organic molecule, reacting with oxidants such as the hydroxyl radical as well as redox-active transition metals such as iron and copper. The literature provides a solid outline for this chemistry, but there are large disagreements about mechanisms, stoichiometries and reaction rates, particularly for the transition metal reactions. Here we synthesize the literature, develop a chemical kinetics model, and use seven sets of laboratory measurements to constrain mechanisms for the iron and copper reactions and derive key rate constants. We find that micromolar concentrations of iron(III) and copper(II) are more important sinks for ascorbic acid (both AH2 and AH−) than reactive oxygen species. The iron and copper reactions are catalytic rather than redox reactions, and have unit stoichiometries: Fe(III)/Cu(II) + AH2/AH− + O2 → Fe(III)/Cu(II) + H2O2 + products. Rate constants are 5.7 × 104 and 4.7 × 104 M−2 s−1 for Fe(III) + AH2/AH− and 7.7 × 104 and 2.8 × 106 M−2 s−1 for Cu(II) + AH2/AH−, respectively.Jiaqi ShenPaul T. GriffithsSteven J. CampbellBattist UtingerMarkus KalbererSuzanne E. PaulsonNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 11, Iss 1, Pp 1-14 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Jiaqi Shen Paul T. Griffiths Steven J. Campbell Battist Utinger Markus Kalberer Suzanne E. Paulson Ascorbate oxidation by iron, copper and reactive oxygen species: review, model development, and derivation of key rate constants
description	Abstract Ascorbic acid is among the most abundant antioxidants in the lung, where it likely plays a key role in the mechanism by which particulate air pollution initiates a biological response. Because ascorbic acid is a highly redox active species, it engages in a far more complex web of reactions than a typical organic molecule, reacting with oxidants such as the hydroxyl radical as well as redox-active transition metals such as iron and copper. The literature provides a solid outline for this chemistry, but there are large disagreements about mechanisms, stoichiometries and reaction rates, particularly for the transition metal reactions. Here we synthesize the literature, develop a chemical kinetics model, and use seven sets of laboratory measurements to constrain mechanisms for the iron and copper reactions and derive key rate constants. We find that micromolar concentrations of iron(III) and copper(II) are more important sinks for ascorbic acid (both AH2 and AH−) than reactive oxygen species. The iron and copper reactions are catalytic rather than redox reactions, and have unit stoichiometries: Fe(III)/Cu(II) + AH2/AH− + O2 → Fe(III)/Cu(II) + H2O2 + products. Rate constants are 5.7 × 104 and 4.7 × 104 M−2 s−1 for Fe(III) + AH2/AH− and 7.7 × 104 and 2.8 × 106 M−2 s−1 for Cu(II) + AH2/AH−, respectively.
format	article
author	Jiaqi Shen Paul T. Griffiths Steven J. Campbell Battist Utinger Markus Kalberer Suzanne E. Paulson
author_facet	Jiaqi Shen Paul T. Griffiths Steven J. Campbell Battist Utinger Markus Kalberer Suzanne E. Paulson
author_sort	Jiaqi Shen
title	Ascorbate oxidation by iron, copper and reactive oxygen species: review, model development, and derivation of key rate constants
title_short	Ascorbate oxidation by iron, copper and reactive oxygen species: review, model development, and derivation of key rate constants
title_full	Ascorbate oxidation by iron, copper and reactive oxygen species: review, model development, and derivation of key rate constants
title_fullStr	Ascorbate oxidation by iron, copper and reactive oxygen species: review, model development, and derivation of key rate constants
title_full_unstemmed	Ascorbate oxidation by iron, copper and reactive oxygen species: review, model development, and derivation of key rate constants
title_sort	ascorbate oxidation by iron, copper and reactive oxygen species: review, model development, and derivation of key rate constants
publisher	Nature Portfolio
publishDate	2021
url	https://doaj.org/article/53a555c11cac48b0be1dacd8ef5ff865
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Ascorbate oxidation by iron, copper and reactive oxygen species: review, model development, and derivation of key rate constants

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