Oxidation-Reduction Potentials of the Metmyoglobin-Myoglobin System

Taylor, John Fuller; Morgan, Vincent E.

doi:10.1016/s0021-9258(18)72551-9

Cited by 65 publications

(20 citation statements)

References 12 publications

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“…In this case, the experimental profiles were accurately described by GSR, yielding ϕ Mb with E 1/2 = −157 mV versus Ag/AgCl, n = 1, in good agreement with the reported value of −153 mV. 40 Control GSR analysis with unrestricted n MG yielded coefficients of 0.9−1.1 without significant impact on E 1/2…”

Section: ■ Resultssupporting

confidence: 85%

“…Here, we illustrate the ability of GSR/NPSV to isolate the contribution of redox mediators and extract an unbiased redox difference spectrum of an unknown analyte using a well-characterized model, Mb, whose NPSV spectrum (Figure 2) is nearly identical to that previously reported using SSV. 4 The NPSV-measured E 1/2 of Mb is also in remarkable agreement with the reported value of −46.0 mV versus NHE 40 obtained by chemical titrations. The overall resolution of a multidimensional technique, such as NPSV, is inherently higher than either spectroscopy or voltammetry separately.…”

Section: ■ Discussionsupporting

confidence: 86%

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Fourier Transform Infrared Spectrovoltammetry and Quantitative Modeling of Analytes in Kinetically Constrained Redox Mixtures

John

Proshlyakov

2019

Anal. Chem.

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Redox-active analytes that do not support direct electron transfer on the electrode, such as proteins with buried redox centers, pose challenges to characterization of their structural and thermodynamic properties. Investigations of indirect transitions in analytes supported by complex redox mixtures require a careful balance between kinetic limitations and spectral interference from the mediators. Using methylene green and thionine acetate as redox mediators and myoglobin as the analyte, we demonstrate that normal pulse spectrovoltammetry (NPSV) with Fourier transform infrared (FT-IR) detection and subsequent global spectral regression analysis can resolve structural and thermodynamic properties simultaneously with little a priori information. Both the E 1/2 and unbiased redox difference FT-IR spectra of the Fe(II)/Fe(III) redox couple of myoglobin in reduction and oxidation NPSV modes were in good agreement with those reported earlier by independent techniques. The thermodynamic and kinetic limitations of mediators/analyte interactions were investigated using comprehensive semiempirical kinetic simulation models. This modeling effort yielded a flexible computational tool capable of quantitatively predicting the redox response in mediated electrochemical studies and defining its limitations, thus greatly expanding the range and precision of the formal mediator/analyte concentration ratio rule.

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Section: ■ Resultssupporting

confidence: 85%

Section: ■ Discussionsupporting

confidence: 86%

Fourier Transform Infrared Spectrovoltammetry and Quantitative Modeling of Analytes in Kinetically Constrained Redox Mixtures

John

Proshlyakov

2019

Anal. Chem.

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“…31 Azide complexes of wild-type and variant sperm whale, pig and human Mbs have been characterized previously. 18,21,28,32 Electrostatic modulation of haem protein reduction potentials is well known. For example, modification of surface lysines with maleate in cytochrome c 33 and the substitution of surface lysines with glutamic acids in cytochrome c 2 34 both caused decreases in the reduction potential of the haem iron.…”

Section: Discussionmentioning

confidence: 99%

“…The value obtained for wild-type Mb agrees well with values reported previously for the horse heart protein. [28][29][30] The absorption spectra collected during the spectroelectrochemical titration of the Lys45Glu/Lys63Glu variant are shown in Fig. 4.…”

Section: Dalton Transactions Papermentioning

confidence: 99%

Engineered metalloregulation of azide binding affinity and reduction potential of horse heart myoglobin

Hunter¹,

Mauk

2013

Dalton Trans.

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Metal ion binding to a previously reported variant of horse heart myoglobin (Lys45Glu/Lys63Glu) with a metal ion binding site on the surface of the protein that is adjacent to the haem binding site has been shown to influence ligand binding and electrochemical properties of the protein. For example, the K(d) (μM) for binding of azide to this variant decreases from 277 ± 9 to 32 ± 3 following addition of a saturating concentration of Mn(2+) (the value for the wild-type protein under the same conditions is 26 ± 1). Similarly, the midpoint reduction potential E(m) (mV vs. standard hydrogen electrode) increases from 9 to 40 in the presence of a saturating concentration of Mn(2+) (the value for the wild-type protein under the same conditions is 45 ± 2). These results demonstrate the potential value of engineered metal ion binding sites as a means of regulating the functional properties of even simple haem proteins.

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“…These rates are highly correlated with their redox potentials. [34] The redox potentials of SO 3 *À /SO 3 2À , met-HbA/HbA, met-Mb/Mb, met-Ngb/Ngb, and met-flavoHb/flavoHb are + 0.73 V, [141] + 0.144 V, [142] + 0.046 V, [143] À 0.129 V, [137] and À 0.125 V [144] respectively. Despite the same redox potentials of Ngb and flavoHbs, the reaction rate of flavoHbs is 4-8-fold greater than Ngb.…”

Section: Heme-globinsmentioning

confidence: 99%

Cross‐talk Between (Hydrogen)Sulfite and Metalloproteins: Impact on Human Health

Maiti

2022

Chemistry A European J

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Sulfite is a potent toxic substance causing harm to multi-organ in human. Despite toxicity, it is widely used as preservative, anti-browning and anti-oxidant in foods, beverages, and pharmaceuticals, which cause easy admission of sulfite in human. Sulfite is also produced endogenously during the catabolism of cysteine and methionine. In vivo, the serum sulfite level at physiological range is strictly maintained by a molybdenum dependent sulfite oxidase (SO), which catalyzes sulfite to sulfate oxidation via a two-electron oxidation pathway. The loss of SO activity causes high serum sulfite level that fosters several diseases, including asthma, neurological dysfunction, birth defects, and heart diseases. The cytotoxicity of (bi)sulfite is implicated as sulfite radicals, which are generated by mainly heme-peroxidases via a oneelectron oxidation pathway. On the other hand, the toxic sulfite radicals are neutralized to sulfite by heme-globins. The enzymatic reduction of sulfite to sulfide is catalyzed by sulfite reductase, which contains an unusual metal cofactor, siroheme-[4Fe4S]-cluster. Overall, the interaction of sulfite with various metalloproteins in vivo is a close relation with human health. Therefore, this review describes the metabolic conversion of (bi)sulfite to sulfate, sulfite radical or sulfide via oxidation or reduction pathways by various metalloproteins (specially SOs, peroxidases, heme-globins, and sulfite reductases), and the potential applications of sulfite in biosensors/ biofuel cells, anti-browning, and advance oxidation process.

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Oxidation-Reduction Potentials of the Metmyoglobin-Myoglobin System

Cited by 65 publications

References 12 publications

Fourier Transform Infrared Spectrovoltammetry and Quantitative Modeling of Analytes in Kinetically Constrained Redox Mixtures

Fourier Transform Infrared Spectrovoltammetry and Quantitative Modeling of Analytes in Kinetically Constrained Redox Mixtures

Engineered metalloregulation of azide binding affinity and reduction potential of horse heart myoglobin

Cross‐talk Between (Hydrogen)Sulfite and Metalloproteins: Impact on Human Health

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