Superoxide Converts Indigo Carmine to Isatin Sulfonic Acid

Kettle, Anthony J.; Clark, Bruce M.; Winterbourn, Christine C.

doi:10.1074/jbc.m400334200

Cited by 129 publications

(52 citation statements)

References 30 publications

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“…IC is a compound with characteristic absorbance at max ϭ 610 nm. It is sensitive to oxidation by singlet oxygen, superoxide anion radical, or by ozone but not by other reactive oxygen species (29,30). As a result of the oxidation, a compound that lacks absorbance at ϭ 610 nm was formed.…”

Section: Peroxidase-like Activity Of Complexes Of Heme With Immunoglomentioning

confidence: 99%

Antibodies Use Heme as a Cofactor to Extend Their Pathogen Elimination Activity and to Acquire New Effector Functions

Dimitrov

Roumenina

Doltchinkova

et al. 2007

Journal of Biological Chemistry

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Various pathological processes are accompanied by release of high amounts of free heme into the circulation. We demonstrated by kinetic, thermodynamic, and spectroscopic analyses that antibodies have an intrinsic ability to bind heme. This binding resulted in a decrease in the conformational freedom of the antibody paratopes and in a change in the nature of the noncovalent forces responsible for the antigen binding. The antibodies use the molecular imprint of the heme molecule to interact with an enlarged panel of structurally unrelated epitopes. Upon heme binding, monoclonal as well as pooled immunoglobulin G gained an ability to interact with previously unrecognized bacterial antigens and intact bacteria. IgG-heme complexes had an enhanced ability to trigger complement-mediated bacterial killing. It was also shown that heme, bound to immunoglobulins, acted as a cofactor in redox reactions. The potentiation of the antibacterial activity of IgG after contact with heme may represent a novel and inducible innate-type defense mechanism against invading pathogens.

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Section: Peroxidase-like Activity Of Complexes Of Heme With Immunoglomentioning

confidence: 99%

Antibodies Use Heme as a Cofactor to Extend Their Pathogen Elimination Activity and to Acquire New Effector Functions

Dimitrov

Roumenina

Doltchinkova

et al. 2007

Journal of Biological Chemistry

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“…Kettle et al suggest a mechanism based on superoxide formation that causes the cleavage of indigo carmine and results in the formation of colorless isatin sulfonic acid [17]. This degradation needs to be considered for the calibration procedure, which will be discussed in Sect.…”

Section: Principle Of the Colorimetric Techniquementioning

confidence: 99%

Local Mass Transfer Phenomena and Chemical Selectivity of Gas‐Liquid Reactions in Capillaries

et al. 2017

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Dedicated to Professor Rüdiger Lange on the occasion of his 65th birthday Gas-liquid reactions in microreactors play an important role in scientific research and industry. Enhancing heat and mass transfer allows overcoming mass transfer limitations in gas-liquid reactions. Mass transfer can be further increased by employing helically coiled capillaries, which induce Dean vortices and improve radial mixing. A colorimetric technique is proposed for gas-liquid reactions in straight and helically coiled capillaries in order to visualize local mass transfer phenomena and concentration distributions. This method is based on the consecutive oxidation of leuco-indigo carmine and enables noninvasive investigation of mass transfer and chemical selectivity in microchannels with high temporal and spatial resolution.

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“…Production of hydroxyl radicals (13) and singlet oxygen (15,16) in secondary reactions of HOCl is possible. Ozone formation by neutrophils has also been suggested (17), although this proposal is controversial (18,19). An alternative view is that O 2 .…”

mentioning

confidence: 99%

Modeling the Reactions of Superoxide and Myeloperoxidase in the Neutrophil Phagosome

Winterbourn

Hampton

Livesey

et al. 2006

Journal of Biological Chemistry

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568

434

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Neutrophils kill bacteria by ingesting them into phagosomes where superoxide and cytoplasmic granule constituents, including myeloperoxidase, are released. Myeloperoxidase converts chloride and hydrogen peroxide to hypochlorous acid (HOCl), which is strongly microbicidal. However, the role of oxidants in killing and the species responsible are poorly understood and the subject of current debate. To assess what oxidative mechanisms are likely to operate in the narrow confines of the phagosome, we have used a kinetic model to examine the fate of superoxide and its interactions with myeloperoxidase. Known rate constants for reactions of myeloperoxidase have been used and substrate concentrations estimated from neutrophil morphology. In the model, superoxide is generated at several mM/s. Most react with myeloperoxidase, which is present at millimolar concentrations, and rapidly convert the enzyme to compound III. Compound III turnover by superoxide is essential to maintain enzyme activity. Superoxide stabilizes at ϳ25 M and hydrogen peroxide in the low micromolar range. HOCl production is efficient if there is adequate chloride supply, but further knowledge on chloride concentrations and transport mechanisms is needed to assess whether this is the case. Low myeloperoxidase concentrations also limit HOCl production by allowing more hydrogen peroxide to escape from the phagosome. In the absence of myeloperoxidase, superoxide increases to >100 M but hydrogen peroxide to only ϳ30 M. Most of the HOCl reacts with released granule proteins before reaching the bacterium, and chloramine products may be effectors of its antimicrobial activity. Hydroxyl radicals should form only after all susceptible protein targets are consumed.

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Superoxide Converts Indigo Carmine to Isatin Sulfonic Acid

Cited by 129 publications

References 30 publications

Antibodies Use Heme as a Cofactor to Extend Their Pathogen Elimination Activity and to Acquire New Effector Functions

Antibodies Use Heme as a Cofactor to Extend Their Pathogen Elimination Activity and to Acquire New Effector Functions

Local Mass Transfer Phenomena and Chemical Selectivity of Gas‐Liquid Reactions in Capillaries

Modeling the Reactions of Superoxide and Myeloperoxidase in the Neutrophil Phagosome

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