NMR Relaxation Measurements as a Tool for Observation of Oxidative Processes

Wierzuchowska, D.; Skórski, L.W.; Blicharska, B.

doi:10.12693/aphyspola.129.226

Cited by 3 publications

(4 citation statements)

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“…After reaching the minimum, T 1 starts to increase as a result of antioxidants' activity. This curve is similar to the time course for protein solutions with the addition of vitamin C [4] and may be interpreted as an action of antioxidants present in tea. In aqueous solutions of proteins (like egg white or bovine serum albumin) the time courses, obtained after the addition of hydrogen peroxide, were well fitted by exponential decays with parameters depending on the type and concentration of proteins.…”

Section: Resultssupporting

confidence: 63%

“…In aqueous solutions of proteins (like egg white or bovine serum albumin) the time courses, obtained after the addition of hydrogen peroxide, were well fitted by exponential decays with parameters depending on the type and concentration of proteins. Adding an antioxidant (e.g., ascorbic acid or glutathione) to protein solutions resulted in a different behavior -after exponential decay and reaching a minimum -an increase of the relaxation times was observed [4]. Similar time courses were measured also in native blood serums which contained the endogenous antioxidants [5].…”

Section: Resultsmentioning

confidence: 56%

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Kinetics of Oxidation and Antioxidation Processes in Biological Solutions Observed by NMR Relaxation

2020

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Preliminary studies on the application of NMR relaxation measurements for observations of the kinetics of oxidation processes in tea samples were performed. Tea is a rich source of flavonoids and other compounds with great antioxidant capacity and is therefore beneficial for human health. Its antioxidant potential depends on the type of tea and the method of preparation. Green and black tea prepared from tea bags brewed in water at 90 • C for 20 and 60 min were examined. Oxidation processes were induced in tea samples by adding 3% H2O2 in 1:10 proportion. Observed time courses of spin-lattice T1 relaxation time and parameters obtained from fitting of combined exponential and compressed-exponential function, depended on kind of tea, brewing time, and milk addition. The obtained results showed the usefulness of the NMR relaxation measurements for observation of oxidation processes and antioxidant activity.

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Section: Resultssupporting

confidence: 63%

Section: Resultsmentioning

confidence: 56%

Kinetics of Oxidation and Antioxidation Processes in Biological Solutions Observed by NMR Relaxation

2020

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“…The increase observed in relaxation time values revealed that the free radical effect was disappearing due to scavenging activity of the antioxidants used [5]. The same phenomenon was observed in the bovine serum albumin solutions [6]. The increase in T 1 was significant in protein solutions with AA, while in the samples with GA was weaker in a time course of experiment.…”

Section: Resultsmentioning

confidence: 66%

Observation of Antioxidants Activity using NMR Relaxation Measurements

2018

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Formation of free radicals in biological solutions leads to the changes in water protons relaxation times. Therefore, NMR relaxation measurements were used to investigate kinetics of oxidation processes induced by the addition, in low amounts, of hydrogen peroxide (H2O2q to aqueous protein solution and to blood serum. The measured relaxation times were not stable over time because of the progressive formation of free radicals and their damaging action to the protein structure. The addition of antioxidants (ascorbic acid, gallic acid etc.) changed the relaxation time courses due to free radical scavenging. Similar time courses, thus anti-oxidant actions, were observed in various blood serum without antioxidant additive. Moreover, the observed kinetics of spin-lattice relaxation time (T1q depended on several factors, such as: structure and concentration of protein solutions and activity and concentration of the added antioxidants.

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“…NMR Relaxation of Nuclei of Buffer as a Probe for Monitoring… the first part of the material and it was labeled as "control", and then, 5 mM of H 2 O 2 was added to the second part to induce oxidation reaction and it was labeled as "oxidized". The oxidized sample was incubated for 24 h before measurements to remove possible contribution in the proton relaxation from paramagnetic oxygen remaining after decomposition of H [34]. The non-reducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to check the oligomeric state of RRM2 in control and oxidized samples.…”

Section: Samplesmentioning

confidence: 99%

NMR Relaxation of Nuclei of Buffer as a Probe for Monitoring Protein Solutions Including Aggregation Processes

et al. 2020

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Characterization of protein solutions is of great importance for biophysical research, pharmaceutical industry, and medicine. Particularly, the monitoring of the protein aggregation is crucial at all stages of biotechnological production and in the diagnosis of dangerous diseases. The present work is focused on a study of prospects and possibilities of NMR relaxation of solvent nuclei for monitoring the state of proteins in solutions. The spin-lattice and spin-spin relaxation rates (R 1 and R 2) of solvent nuclei were measured in the solutions of a small globular protein, RRM2 domain of TDP-43 protein. The solvent was either H 2 O-or D 2 O-based buffer with pH 6.5 and contained 20 mM sodium phosphate and 150 mM NaCl. The relaxation rates of the solvent 1 H, 2 H, 23 Na, and 35 Cl nuclei in solutions of soluble and aggregated RRM2 domain of TDP-43 protein were studied. The aggregation was induced by mild oxidative stress, using treatment by hydrogen peroxide. It was found that aggregation of protein could be detected using NMR relaxation of 1 H nuclei. The observed CPMG dispersion for R 2 rates confirms the millisecond timescale for the hydrogen exchange between water and protein sites. The correlation times and binding constants for sodium and chlorine ions were estimated using concentration dependences for relaxation rates (23 Na, 35 Cl). The relaxation rates of solvent nuclei are sensitive to the presence of protein in solution even at low protein concentrations, and the relaxation rates of different nuclei reflect various aspects of the state of the protein.

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NMR Relaxation Measurements as a Tool for Observation of Oxidative Processes

Cited by 3 publications

References 5 publications

Kinetics of Oxidation and Antioxidation Processes in Biological Solutions Observed by NMR Relaxation

Kinetics of Oxidation and Antioxidation Processes in Biological Solutions Observed by NMR Relaxation

Observation of Antioxidants Activity using NMR Relaxation Measurements

NMR Relaxation of Nuclei of Buffer as a Probe for Monitoring Protein Solutions Including Aggregation Processes

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