Electron Spin Resonance Studies of Free Radicals in γ-Irradiated Soybean Paste

Lee, Eunjoo; Volkov, V. I.; Lee, Cherl‐Ho

doi:10.1021/jf010227t

Cited by 8 publications

(5 citation statements)

References 15 publications

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“…The group fed irradiated soybeans had elevated levels of oxidation in liver lipids, DNA oxidative damage, as well as myelin figures and swollen mitochondria in parietal and intestinal epithelial cells. Lee and others (2001, 2002) demonstrated that dry soybean paste exposed to γ‐irradiation resulted in trapped radicals. Farrow and Davis (1990) found that an increased risk of pancreatic cancer was associated with increased protein intake in general in men.…”

Section: Resultsmentioning

confidence: 99%

Carbon‐Centered Radicals in Isolated Soy Proteins

Boatright¹,

Jahan²,

Walters³

et al. 2008

Journal of Food Science

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Solid-state electron paramagnetic resonance (EPR) spectroscopy of commercial samples of isolated soy proteins (ISP) revealed a symmetrical free-radical signal typical of carbon-centered radicals (g= 2.005) ranging from 2.96 x 10(14) to 6.42 x 10(14) spins/g. The level of free radicals in ISP was 14 times greater than similar radicals in sodium caseinate, 29 times greater than egg albumin, and about 100 times greater levels than casein. Nine soy protein powdered drink mixes contained similar types of free radicals up to 4.10 x 10(15) spins/g of drink mix, or up to 6.4 times greater than the highest free-radical content found in commercial ISP. ISP samples prepared in the laboratory contained trapped radicals similar to the levels in commercial ISP samples. When ISP was hydrated in 2.3 mM sodium erythorbate or 8.3 mM L-cysteine, frozen and dried, the level of trapped free radicals increased by about 17- and 19-fold, respectively. The ESR spectrum of defatted soybean flakes contained overlapping signals from the primary free-radical peak (g= 2.005) and a sextet pattern typical of manganese-II. The manganese signal was reduced in the laboratory ISP and very weak in the commercial ISP.

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Section: Resultsmentioning

confidence: 99%

Carbon‐Centered Radicals in Isolated Soy Proteins

Boatright¹,

Jahan²,

Walters³

et al. 2008

Journal of Food Science

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“…All the irradiation experiments were conducted under ambient temperature in the facility rooms, but during electron-only irradiation, temperature increased up to 50°C in the 500 kGy samples for 10 s. It is known that the sample temperature may affect the free radical formation rate (Lee et al , 2001 ) mainly in liquid state and, therefore, the preservation of the activity of the molecules (Kempner et al , 1986 ). However, considering that all our samples were in dry state, and we irradiated them in a narrow stretch of temperatures, the production of free radicals and their effect on the structure of the compounds are expected to be proportional to radiation dose but, mostly, negligible.…”

Section: Discussionmentioning

confidence: 99%

Effects of Gamma and Electron Radiation on the Structural Integrity of Organic Molecules and Macromolecular Biomarkers Measured by Microarray Immunoassays and Their Astrobiological Implications

et al. 2018

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High-energy ionizing radiation in the form of solar energetic particles and galactic cosmic rays is pervasive on the surface of planetary bodies with thin atmospheres or in space facilities for humans, and it may seriously affect the chemistry and the structure of organic and biological material. We used fluorescent microarray immunoassays to assess how different doses of electron and gamma radiations affect the stability of target compounds such as biological polymers and small molecules (haptens) conjugated to large proteins. The radiation effect was monitored by measuring the loss in the immunoidentification of the target due to an impaired ability of the antibodies for binding their corresponding irradiated and damaged epitopes (the part of the target molecule to which antibodies bind). Exposure to electron radiation alone was more damaging at low doses (1 kGy) than exposure to gamma radiation alone, but this effect was reversed at the highest radiation dose (500 kGy). Differences in the dose–effect immunoidentification patterns suggested that the amount (dose) and not the type of radiation was the main factor for the cumulative damage on the majority of the assayed molecules. Molecules irradiated with both types of radiation showed a response similar to that of the individual treatments at increasing radiation doses, although the pattern obtained with electrons only was the most similar. The calculated radiolysis constant did not show a unique pattern; it rather suggested a different behavior perhaps associated with the unique structure of each molecule. Although not strictly comparable with extraterrestrial conditions because the irradiations were performed under air and at room temperature, our results may contribute to understanding the effects of ionizing radiation on complex molecules and the search for biomarkers through bioaffinity-based systems in planetary exploration.

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“…Using the combined techniques of on-line high-performance liquid chromatography/electron spin resonance and mass spectrometry (LC/ESR and LC/MS), Qian et al ( , ) identified spin trapped lipid-derived carbon-centered radicals formed in linoleic acid peroxidation and the reactions of two ω-6 polyunsaturated fatty acids (linoleic and arachidonic acids) with soybean lipoxygenase in the presence of α-[4-pyridyl 1-oxide]- N - t -butyl nitrone. Polat and Korkmaz () used ESR spectroscopy to study kinetics of radiation-induced free radical and Mn 2+ signals in γ-irradiated ground soybeans at a temperature range of 130−400 K. Lee et al ( , ) investigated free radicals in γ-irradiated soybean paste by ESR spectroscopy and compared it with those of soybean protein isolate and soybean oil to examine the influences of irradiation dose, moisture content, and heating after irradiation of the free radical concentration and species.…”

Section: Introductionmentioning

confidence: 99%

Detection of Free Radical Transfer in Lipoxygenase I-B-Catalyzed Linoleic Acid−Soybean Protein Interaction by Electron Spin Resonance Spectroscopy (ESR)

Huang

Hua

et al. 2006

J. Agric. Food Chem.

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Effects of lipoxygenase I-B (LOX)-catalyzed oxidation of linoleic acid on soybean proteins was evaluated by electron spin resonance (ESR) and fluorescence spectroscopy in different model systems in the presence or absence of antioxidants. A strong central singlet signal was detected by ESR spectroscopy and identified as the carbon radical (g value range 2.0041-2.0054). A downfield shoulder attributed to the sulfur radical (g value 2.019-2.028) was also observed. The changes in soybean proteins were accompanied by an increase in fluorescence, indicating the formation of cross-links. Natural antioxidants such as ascorbic acid and alpha-tocopherol as well as synthetic antioxidants butyl hydroxytoluene (BHT) inhibited the development of both the free radical signal and the fluorescence when added to soybean proteins prior to incubation with linoleic acid and lipoxygenase I-B; the central singlet signal attributed to the carbon radical was reduced by 35-65%. This paper clearly indicates direct free radical transfer from oxidizing linoleic acid catalyzed by LOX to soybean proteins.

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Electron Spin Resonance Studies of Free Radicals in γ-Irradiated Soybean Paste

Cited by 8 publications

References 15 publications

Carbon‐Centered Radicals in Isolated Soy Proteins

Carbon‐Centered Radicals in Isolated Soy Proteins

Effects of Gamma and Electron Radiation on the Structural Integrity of Organic Molecules and Macromolecular Biomarkers Measured by Microarray Immunoassays and Their Astrobiological Implications

Detection of Free Radical Transfer in Lipoxygenase I-B-Catalyzed Linoleic Acid−Soybean Protein Interaction by Electron Spin Resonance Spectroscopy (ESR)

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