Chemistry of Reactive Species

Villamena, Frederick A.

doi:10.1002/9781118355886.ch1

“…Ultraweak chemiluminescence (CL) and bioluminescence (BL) are fundamentally related, because some of the free radicals involved in CL 15 , 26 , 31 – 33 are also essential for biological processes such as single-electron transfer, oxidative phosphorylation, redox homeostasis, oxidative stress, or cell signaling 34 . Among them, hydrogen peroxide ( ) is a radical-based reactive oxygen species (ROS) that plays a key role in both chemistry and biology, most likely because it is much more stable compared to other ROS.…”

Section: Resultsmentioning

confidence: 99%

“…In particular, while acts as biological messenger for many cellular responses, it is also involved in the oxidative stress response which comes with toxic effects, and it is enzymatically degraded by catalase or myeloperoxidase during detoxification processes 34 , 35 . While non-enzymatic degradation also occurs in aqueous solution by the luminescent metal-catalyzed Fenton reaction, or through the radical-mediated oxidation of various anions or proteins 15 , 26 , 32 , 34 , one single report shows evidence that the non-catalytic disproportionation of in salt solutions produces a very weak chemiluminescence 36 . This luminescence is most likely due to electronic transitions of singlet oxygen 26 , 36 , 37 .…”

Section: Resultsmentioning

confidence: 99%

Stochastic light concentration from 3D to 2D reveals ultraweak chemi- and bioluminescence

Khaoua

¹

,

Graciani

²

,

Kim

³

et al. 2021

Sci Rep

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For countless applications in science and technology, light must be concentrated, and concentration is classically achieved with reflective and refractive elements. However, there is so far no efficient way, with a 2D detector, to detect photons produced inside an extended volume with a broad or isotropic angular distribution. Here, with theory and experiment, we propose to stochastically transform and concentrate a volume into a smaller surface, using a high-albedo Ulbricht cavity and a small exit orifice through cavity walls. A 3D gas of photons produced inside the cavity is transformed with a 50% number efficiency into a 2D Lambertian emitting orifice with maximal radiance and a much smaller size. With high-albedo quartz-powder cavity walls ($$\rho =99.94\%$$ ρ = 99.94 % ), the orifice area is $$1/(1-\rho )\approx 1600$$ 1 / ( 1 - ρ ) ≈ 1600 times smaller than the walls’ area. When coupled to a detectivity-optimized photon-counter ($$\mathcal{D}=0.015\,{\text{photon}}^{-1}\,{\text{s}}^{1/2}\text{ cm}$$ D = 0.015 photon - 1 s 1 / 2 cm ) the detection limit is $$110\;{\text{photon}}\;{\text{s}}^{ - 1} \;{\text{L}}^{ - 1}$$ 110 photon s - 1 L - 1 . Thanks to this unprecedented sensitivity, we could detect the luminescence produced by the non-catalytic disproportionation of hydrogen peroxide in pure water, which has not been observed so far. We could also detect the ultraweak bioluminescence produced by yeast cells at the onset of their growth. Our work opens new perspectives for studying ultraweak luminescence, and the concept of stochastic 3D/2D conjugation should help design novel light detection methods for large samples or diluted emitters.

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“…On the other hand, Swamy and Surolia [ 52 ] proposed that decrease in fluorescence results from the exposure of tryptophanyl residues to the solvent molecules that collide with fluorophores and consume fluorescence energy. The decrease could also be induced by oxidation, since the indole ring of Trp and side chain of Tyr are susceptible to oxidative damage by ROS [ 53 ].…”

Section: Resultsmentioning

confidence: 99%

Rapid Myoglobin Aggregation through Glucosamine-Induced α-Dicarbonyl Formation

Hrynets

¹

,

Ndagijimana

²

,

Betti

³

2015

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The extent of glycation and conformational changes of horse myoglobin (Mb) upon glycation with N-acetyl-glucosamine (GlcNAc), glucose (Glc) and glucosamine (GlcN) were investigated. Among tested sugars, the rate of glycation with GlcN was the most rapid as shown by MALDI and ESI mass spectrometries. Protein oxidation, as evaluated by the amount of carbonyl groups present on Mb, was found to increase exponentially in Mb-Glc conjugates over time, whereas in Mb-GlcN mixtures the carbonyl groups decreased significantly after maximum at 3 days of the reaction. The reaction between GlcN and Mb resulted in a significantly higher amount of α-dicarbonyl compounds, mostly glucosone and 3-deoxyglucosone, ranging from and 27 to 332 mg/L and from 14 to 304 mg/L, respectively. Already at 0.5 days, tertiary structural changes of Mb-GlcN conjugate were observed by altered tryptophan fluorescence. A reduction of metmyoglobin to deoxy-and oxymyoglobin forms was observed on the first day of reaction, coinciding with the greatest amount of glucosone produced. In contrast to native α-helical myoglobin, 41% of the glycated protein sequence was transformed into a β-sheet conformation, as determined by circular dichroism spectropolarimetry. Transmission electron microscopy demonstrated that Mb glycation with GlcN causes the formation of amorphous or fibrous aggregates, started already at 3 reaction days. These aggregates bind to an amyloid-specific dye thioflavin T. With the aid of α-dicarbonyl compounds and advanced products of reaction, this study suggests that the Mb glycation with GlcN induces the unfolding of an initially globular protein structure into amyloid fibrils comprised of a β-sheet structure.

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“…Reactive oxygen species (ROS) are partially reduced metabolites of molecular oxygen formed in biological systems as a result of a normal cellular metabolism, primarily in the mitochondria [24]. Exogenous sources such as pollutants [25], smoke [26], radiation [27] or heavy metals [28] also may increase the ROS levels.…”

Section: Manganese Superoxide Dismutases Peroxidases and Catalasesmentioning

confidence: 99%

Pursuing the Elixir of Life: In Vivo Antioxidative Effect of Manganosalen Complexes, a Review

Rouco¹,

Pedrido²,

Maneiro³

2020

Preprint

6

0

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Manganosalen complexes are coordination compounds that possess a chelating salen-type ligand, a class of bis-Schiff bases obtained by condensation of salicylaldehyde and a diamine. They may act as catalytic antioxidants mimicking both the structure and the reactivity of the native antioxidant enzymes active site. Thus, manganosalen complexes have shown to exhibit superoxide dismutase, catalase, and glutathione peroxidase activities, and they could potentially facilitate the scavenging of excess ROS, thereby restoring the redox balance in the damaged cells and organs. Initial catalytic studies compared the potency of these compounds as antioxidants in terms of rate constants of the chemical reactivity against ROS, giving catalytic values approaching and even exceeding that of the native antioxidative enzymes. Although most of these catalytic studies lack of biological relevance, subsequent in vitro studies have confirmed the efficiency of many manganosalen complexes in oxidative stress models. These synthetic catalytic scavengers, cheaper than natural antioxidants, have accordingly attracted intensive attention for the therapy of ROS-mediated injuries. The aim of this review is to focus on in vivo studies performed on manganosalen complexes and their activity on the treatment of several pathological disorders associated with oxidative damage. This disorders, ranging from the prevention of fetal malformations to the extension of lifespan, include neurodegenerative, inflammatory and cardiovascular diseases, tissue injury, and other damages related to liver, kidney or lungs.

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Chemistry of Reactive Species

Cited by 15 publications

References 271 publications

Stochastic light concentration from 3D to 2D reveals ultraweak chemi- and bioluminescence

Stochastic light concentration from 3D to 2D reveals ultraweak chemi- and bioluminescence

Rapid Myoglobin Aggregation through Glucosamine-Induced α-Dicarbonyl Formation

Pursuing the Elixir of Life: In Vivo Antioxidative Effect of Manganosalen Complexes, a Review

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