The Utility of Superoxide Dismutase in Studying Free Radical Reactions

McCord, Joe M.; Fridovich, Irwin

doi:10.1016/s0021-9258(18)63246-6

Cited by 256 publications

(5 citation statements)

References 18 publications

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“…To investigate if photo-generated electrons can be transferred from QD to redox active proteins we tested two proteins, with different redox potentialspinach Fd and Cyt c from bovine heart. It is known, that Cyt c may be reduced by superoxide, 19 which can be created by electron transfer from QDs to oxygen.…”

Section: Spectrophotometric Characterization Of Ferredoxin and Cytoch...mentioning

confidence: 99%

Photoreduction of natural redox proteins by CdTe quantum dots is size-tunable and conjugation-independent

2015

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Colloidal CdTe quantum dots (QD) were able to reduce both heme and iron-sulfur cluster containing proteins. Reduction was depended on quantum dots size. CdTe nanocrystals emitting light with maximum at 550 nm (QD-550, r $ 1.5 nm) reduced both ferredoxin (Fd) and cytochrome c (Cyt c). The process was followed by UV/Vis absorption spectroscopy and steady state fluorescence spectroscopy. For CdTe emitting longer wavelength (QD-610 and QD-670) reduction of Fd was less efficient. QD emitting light with maximum at 750 nm (QD-750, r $ 3.3 nm) reduced only Cyt c. Reduction of proteins by QDs was photo-dependent and did not demand oxygen presence. As shown by gel filtration and fluorescence correlation spectroscopy, Fd formed complexes with QD while Cyt c did not bound steadily. The stable complex was not necessary for photoreduction, although might influence its kinetics.Time-resolved fluorescence studies showed than electron transfer rate depends on QD size and also is higher for QD-Cyt c when compared to QD-Fd. The mechanism of process was additionally explored by detailed analysis of QD-protein complex formation and by measurements of cyclic voltamperometry and zeta potential. These results open new possibilities in controlling of natural redox processes. † Electronic supplementary information (ESI) available: Fluorescence analysis of fraction from gel ltration, example of FCS curves, example of uorescence decay curves. See

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Section: Spectrophotometric Characterization Of Ferredoxin and Cytoch...mentioning

confidence: 99%

Photoreduction of natural redox proteins by CdTe quantum dots is size-tunable and conjugation-independent

2015

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“…Quinones, flavins, and phenazines are excellent sources of single electrons and reduce oxygen rapidly to produce superoxide and hydrogen peroxide. [10][11][12][13][14][15] Chlorite also has the potential to react with AH 2 DS, forming hypochlorite, which is a strong oxidant and reacts with many biomolecules including proteins and lipids. 16,17 Potential reactions are shown in reactions (1)-(3), all of which produce reactive oxygen species (ROS) that are toxic to bacteria.…”

Section: Acetate Stimulates Ah 2 Ds Oxidation In Bioelectrical Reactorsmentioning

confidence: 99%

Bioelectrical redox cycling of anthraquinone-2,6-disulfonate coupled to perchlorate reduction

Clark

Carlson

Iavarone

et al. 2012

Energy Environ. Sci.

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“…limit (Klug et al, 1972;Rotilio et al, 1972). Since several enzymatic Fridovich, 1968, 1969; Hirata and Hayaishi, 1971; Massey et al, 1969) and nonenzymatic (Ballou et al, 1969;McCord and Fridovich, 1970;Fridovich, 1972a,b,c, 1971;Nishikimi et al, 1972; Orme-Johnson and Beinert, 1969; Nilsson et al, 1969;Wever et al, 1973;Heikkila and Cohen, 1973) reactions, of relevance to biological systems, generate O2-, it was reasonable to propose that O2is one of the causes of oxygen toxicity and that superoxide dismutase is the defense which minimizes the danger from this reactive radical. This theory has been supported by studies of its distribution , by studies of mutants with a temperature-sensitive defect in this enzyme (McCord et al, 1973) and by the observations that its induction in bacteria (Gregory and Fridovich, 1973), yeast (Gregory et al, 1974), and rat lung (Crapo and Tierney, 1973) was correlated with enhanced resistance toward hyperbaric oxygen.…”

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confidence: 99%

Production of superoxide radical during the decomposition of potassium peroxochromate(V)

Hodgson¹,

Fridovich²

1974

Biochemistry

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The decomposition of potassium tetraperoxochromate(V) in aqueous solutions generates a reductant of ferricytochrome c as well as an oxidant of ferrocytochrome c. The reductant was intercepted by superoxide dismutase and is presumed to be O2-. The oxidant was scavenged by azide or histidine, which are known to react rapidly with singlet oxygen, and is therefore presumed to be the singlet oxygen which has already been demonstrated to be a product of this decomposition. Decomposition of the perchromate ion was accompanied by a ¡Superoxide dismutases have been shown to catalyze the reaction: 03-4-2~4 • 2H+ -* H2O2 4~O 2, at a rate (k.2 = 2 X 109 M-1 sec-1) which approaches the theoretical diffusion

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The Utility of Superoxide Dismutase in Studying Free Radical Reactions

Cited by 256 publications

References 18 publications

Photoreduction of natural redox proteins by CdTe quantum dots is size-tunable and conjugation-independent

Photoreduction of natural redox proteins by CdTe quantum dots is size-tunable and conjugation-independent

Bioelectrical redox cycling of anthraquinone-2,6-disulfonate coupled to perchlorate reduction

Production of superoxide radical during the decomposition of potassium peroxochromate(V)

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