Bromination and chlorination reactions of myeloperoxidase at physiological concentrations of bromide and chloride
Abstract
Myeloperoxidase and eosinophil peroxidase use hydrogen peroxide to oxidize halides and thiocyanate to their respective hypohalous acids. Myeloperoxidase produces mainly hypochlorous acid and hypothiocyanite. Hypobromous acid and hypothiocyanite are the major products of eosinophil peroxidase. We have investigated the ability of myeloperoxidase to produce hypobromous acid in the presence of physiological concentrations of chloride and bromide. In accord with previous studies, between pH 5 and 7, myeloperoxidase converted about 90% of available hydrogen peroxide to hypochlorous acid and the remainder to hypobromous acid. Above pH 7, there was an abrupt rise in the yield of hypobromous acid. At pH 7.8, it accounted for 40% of the hydrogen peroxide. Bromide, at physiological concentrations, promoted a dramatic increase in bromination of human serum albumin catalyzed by myeloperoxidase. The level of 3-bromotyrosine increased to 16-fold greater than that for 3-chlorotyrosine. Chlorination of tyrosyl residues was not affected by bromide. With reagent hypohalous acids, bromination of tyrosyl residues was considerably more facile than chlorination. Hypochlorous acid promoted bromination to only a limited extent, which ruled out transhalogenation as a substantive route to 3-bromotyrosine. Chloramines and bromamines were also formed on albumin. Bromamines decayed much faster than chloramines and rapidly gave rise to protein carbonyls. We conclude that at physiological concentrations of chloride and bromide, hypobromous acid can be a major oxidant produced by myeloperoxidase. Its production in vivo will depend on pH and the concentration of bromide. Once produced, hypobromous acid will react with proteins to form bromamines, carbonyls, and brominated tyrosine residues. Consequently, 3-bromotyrosine should be considered as an oxidative product of myeloperoxidase and cannot be used as a specific biomarker for eosinophil peroxidase.
Integrity signals
Registry
Cites
Statistics
Claims the paper makes
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
At plasma concentrations of thiocyanate and chloride, myeloperoxidase is far from saturated.
“This indicates that at plasma concentrations of thiocyanate and chloride, myeloperoxidase is far from saturated.”
From The Role of Reactive Species on Innate Immunity (2022) · cites this paper as [170]
The percentage of MPO-induced H2O2 loss in the presence of 100 mM Cl− doubled when 100 μM thiocyanate was added and was maximal at 1 mM thiocyanate.
“The percentage of MPO-induced H2O2 loss in the presence of 100 mM Cl− doubled when 100 µM thiocyanate was added and was maximal at 1 mM thiocyanate.”
From The Role of Reactive Species on Innate Immunity (2022) · cites this paper as [170]
Thiocyanate is an important physiological substrate of MPO.
“Thus, thiocyanate is an important physiological substrate of MPO [170,171].”
From The Role of Reactive Species on Innate Immunity (2022) · cites this paper as [170]
At 100 μM thiocyanate, roughly 50% of peroxide is transformed into hypothiocyanite, and the quantity of hypohalogenic acid production was equal to the sum of the individual rates obtained when each negative ion was present alone.
“At 100 µM thiocyanate, roughly 50% of peroxide is transformed into hypothiocyanite, and the quantity of hypohalogenic acid production was equal to the sum of the individual rates obtained when each of these negative ions was present alone.”
From The Role of Reactive Species on Innate Immunity (2022) · cites this paper as [170]
The relative specificity constants for chloride, bromide, and thiocyanate are 1:60:730, respectively, with thiocyanate being the most favoured substrate for MPO.
“The relative specificity constants for chloride, bromide, and thiocyanate are 1:60:730, respectively, with thiocyanate being the most favoured substrate for MPO.”
From The Role of Reactive Species on Innate Immunity (2022) · cites this paper as [170]
In the presence of 100 mM Cl−, MPO catalyses hypothiocyanite production at thiocyanate concentrations of 25 μM.
“In the presence of 100 mM Cl−, MPO catalyses the hypothiocyanite production at thiocyanate concentrations of 25 µM.”
From The Role of Reactive Species on Innate Immunity (2022) · cites this paper as [170]
The citation lists haven’t been fetched yet
References 54 · Cited by 122
- Authors
- Senthilmohan, R., & Kettle, A. J.
- Affiliations
- University of Otago (NZ)
- ORCID
- Kettle, Anthony J.
- Venue
- Archives of Biochemistry and Biophysics
- Publisher
- Elsevier BV
- Published
- 2006-01
- Volume
- 445
- Issue
- 2
- Pages
- 235-244
- ISSN
- 0003-9861 (ISSN-L)
- OpenAlex
- W1963847375
- Cited by
- 122
- References
- 54
- Citations by year
- 2026: 3 · 2025: 3 · 2024: 4 · 2023: 5 · 2022: 8 · 2021: 3 · 2020: 9 · 2019: 7 · 2018: 1 · 2017: 5 · 2016: 4 · 2015: 9 · 2014: 5 · 2013: 7 · 2012: 9
- FWCI
- 2.36
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Archives of Biochemistry and Biophysics (publishedVersion)
- PubMed (publishedVersion)
- Funders
- Health Research Council of New Zealand
- Topics
- Life Sciences › Immunology and Microbiology › Immunology › Neutrophil, Myeloperoxidase and Oxidative Mechanisms
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Redox biology and oxidative stress
- Physical Sciences › Chemistry › Inorganic Chemistry › Vanadium and Halogenation Chemistry
- Keywords
- myeloperoxidase, eosinophil peroxidase, hypobromous acid, hypochlorous acid, hypohalous acids, bromide, chloride, human serum albumin, 3-chlorotyrosine, bromamines, chloramines, protein carbonylation, pH dependence, protein oxidation, biomarkers
- MeSH terms
- Body Fluids, Bromates, Bromides, Chlorides, Hydrogen Peroxide, Hydrogen-Ion Concentration, Hypochlorous Acid, Peroxidase, Oxidation-Reduction, Serum Albumin
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
