• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.2
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• pp.116-120
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• 2004

In order to investigate low molecular antioxidants synthesized by enhanced UV-B radiation, we used the seedlings of two rice varieties. Woonjangbyeo, UV-tolerant, and Hwajoongbyeo, UV-susceptible, were subjected under supplemental UV-B irradiation. When rice seedlings were irradiated with UV light for short period, biosynthesis of total phenolic compound, ascorbate and glutathione were momently reduced. With an increase of UV-B radiation, however, those were slightly synthesized. The content of lipid peroxides in UV-challenged rice leaves was considerably increased after 12 hrs of UV-B treatment. Lipoxygenase activity under supplemental UV-B radiation was differently responded on rice varieties.

• Molecules and Cells
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• v.39 no.1
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• pp.20-25
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• 2016

Photosynthesis is a highly robust process allowing for rapid adjustment to changing environmental conditions. The efficient acclimation depends on balanced redox metabolism and control of reactive oxygen species release which triggers signaling cascades and potentially detrimental oxidation reactions. Thiol peroxidases of the peroxiredoxin and glutathione peroxidase type, and ascorbate peroxidases are the main peroxide detoxifying enzymes of the chloroplast. They use different electron donors and are linked to distinct redox networks. In addition, the peroxiredoxins serve functions in redox regulation and retrograde signaling. The complexity of plastid peroxidases is discussed in context of suborganellar localization, substrate preference, metabolic coupling, protein abundance, activity regulation, interactions, signaling functions, and the conditional requirement for high antioxidant capacity. Thus the review provides an opinion on the advantage of linking detoxification of peroxides to different enzymatic systems and implementing mechanisms for their inactivation to enforce signal propagation within and from the chloroplast.

• Molecules and Cells
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• v.39 no.1
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• pp.26-30
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• 2016

Peroxiredoxins are ubiquitous thiol proteins that catalyse the breakdown of peroxides and regulate redox activity in the cell. Kinetic analysis of their reactions is required in order to identify substrate preferences, to understand how molecular structure affects activity and to establish their physiological functions. Various approaches can be taken, including the measurement of rates of individual steps in the reaction pathway by stopped flow or competitive kinetics, classical enzymatic analysis and measurement of peroxidase activity. Each methodology has its strengths and they can often give complementary information. However, it is important to understand the experimental conditions of the assay so as to interpret correctly what parameter is being measured. This brief review discusses different kinetic approaches and the information that can be obtained from them.

• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.2
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• pp.148-155
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• 1991

Lipid oxidation and browning during fermentation of domestic Meju and Doenjang were examined in order to elucidate the antioxidative effects of browning products and phenol compounds from Meju and Doenjang. Peroxide values of lipids from Meju were detectable and slightly increased until 3 weeks of fermentation, but started to be decreased after 3 weeks of fermentation and notdetectable after 6 weeks. Peroxides were not detected in Doenjang during the whole fermentation, but started to be decreased after 3 weeks of period of 22 weeks fermentation. Carbonyl value were increased during the whole period of Meju fermentation, but started to be decreased at the early stage of Doenjang fermentation. Hydrophilic fraction of browning products from Meju was much higher than lipophilic fraction and the former fraction was dramatically increased at the early stage of the fermentation. But the both fractions maintained high values during Doenjang fermentation. Hydrophilic browning products and phenol and phenol compound in Meju showed strong antioxidative against linoleic acid.

• Bulletin of the Korean Chemical Society
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• v.20 no.6
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• pp.696-700
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• 1999

A method has been developed for the determination of trace anion impurities in concentrated hydrogen peroxide. The method involves on-line decomposition of hydrogen peroxide, ion chromatographic separation and subsequent suppressed-type conductivity detection. H2O2 is decomposed in Pt-catalyst filled Gore-Tex membrane tubing and the resulting aqueous solution containing analytes is introduced to the injection valve of an ion chromatograph for periodic determinations. The oxygen gas evolving within the membrane tubing escapes freely through the membrane wall causing no problem in ion chromatographic analysis. Decomposition efficiency is above 99.99% at a flow rate of 0.4mL/min for a 30% hydrogen peroxide concentration. Analytes are quantitatively retained. The analysis results for several brands of commercial hydrogen peroxides are reported.

• BMB Reports
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• v.55 no.9
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• pp.413-416
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• 2022

Ferroptosis is a type of programmed cell death distinct from apoptosis or necroptosis. Ferroptosis is well characterized by an iron-dependent accumulation of lipid peroxides and disruption of cellular membrane integrity. Many metabolic alterations can prevent or accelerate ferroptosis induction. Recent advances in analytical techniques of mass spectrometry have allowed high-throughput analysis of metabolites known to be critical for understanding ferroptosis regulatory metabolism. In this review, we introduce mass spectrometry-based analytical methods contributing to recent discovery of various metabolic pathways regulating ferroptosis, focusing on cysteine metabolism, antioxidant metabolism, and poly-unsaturated fatty acid metabolism.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.159-164
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• 2023

Ferroptosis is a type of regulated cell death recently discovered, characterized by the accumulation of iron-dependent lipid peroxides in the cell membrane, and it involves a complex network of signaling pathways, including iron metabolism, lipid peroxidation, and redox regulation. The dysregulation of these pathways can lead to the induction of ferroptosis and the development of liver diseases, such as alcoholic liver disease, non-alcoholic fatty liver disease, viral hepatitis, and liver cancer. Studies have demonstrated that targeting key molecules involved in iron metabolism, lipid peroxidation, and redox regulation can reduce liver injury and improve liver function in different liver diseases by inhibiting ferroptosis. Thus, modulation of ferroptosis presents a promising therapeutic target for treating liver diseases. However, further research is required to gain a more comprehensive understanding of the mechanisms underlying the role of ferroptosis in liver diseases and to develop more effective and targeted treatments.

• Korean Journal of Food Science and Technology
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• v.5 no.2
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• pp.129-135
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• 1973

The accumulation of peroxides, acid values, and carbonyl values during irradiation and post-irradiation storage of the ricebran oil has been studied. The rice bran oils were irradiated two doses of 2 and 7 megarads (300 rads/sec) at $23^{\circ}C$ atmospheric circumstance. The acid values, peroxide values and carbonyl values were measured at regular intervals of one week during the storage at $5^{\circ}C$ and $25^{\circ}C$. 1) During the storage, the acid values of the irradiated rice bran oils increased or decreased insignificantly regardless of the addition of antioxidants and storage temperature. 2) The peroxide values were not increased continuously but increased zigzag. The result was indicated that the composition and decomposition of peroxides occurred continuously throughout the storage. 3) As the peroxide values increased, carbonyl values decreased and changed quite differently, but, especially in 7th week, they were constant or insignificant. 4) Dibutylhydroxytoluene is more effective than caffeic acid in retarding the formation of peroxides during irradiation of rice bran oils and post-irradiation storage. The effect of antioxidant is more efficient at 2 megarads than at 7 megarads irradiation. When we store the rice bran oil, the addition of antioxidants of post-irradiation is more desirable than that of preirradiation. 5) In spite of changing conditions such as storage temperature and addition of antioxidants, the peroxide values of rice bran oils irradiated at 2 megarads were always greater than those at 7 megarads during the storage. Peroxide values of samples at high temperature $(25^{\circ}C)$ storage increased as twice as those of low temperature $(5^{\circ}C)$ storage samples. At low temperature, peroxide values in the first week increased twice during the period of 8th weeks storage, but those did from three to four times at higher temperature in the same period Therefore, the low temperature storage is recommandable too.

• Applied Biological Chemistry
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• v.48 no.4
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• pp.358-363
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• 2005

Effects on the feeds of streptozotocin-induced diabetic rats with a giant embryonic rice on lipid peroxides level and antioxidative enzyme activites in plasma and liver tissues were investigated. Along with the experimental periods, all animals in diabetic groups had a lower increase rate in body weight than the normal control group. A giant embryonic rice-fed group showed a inhibition in the decrease of body weight, and a increase in feed intake compared to the normal control group. The organ weights of the diabetic control group were heavier than those of the normal control while rice-fed groups including the giant embryonic rice-fed group were found to have lower organ weights, and its blood sugar level was found to be lower than those of the normal group. Lipid peroxides of the giant embryonic rice-fed animals showed a lower lipid peroxidation values compared to that of the diabetic control group. Plasma vitamin A and E concentrations of the diabetic control group were significantly decreased compared to the normal control while those of the giant embryonic rice-fed group were found to be significantly higher than those of the diabetic control. Of the hepatic antioxidative enzymes, SOD activity of the giant embryonic rice-fed group was higher than that of the diabetic control group. Taken these together, low lipid peroxidation values and, in contrast, high antioxidative enzyme activities were thought to be a cause for decreasing hepatic oxidative damages.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.2
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• pp.146-151
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• 1987

The storage stability of sardine oil and the effect of BHA on the oxidation of fatty acids especially, highly unsatureted fatty acids like EPA and DHA were investigated. The sardine oil was extracted from round sardine, with chloroform-methanol(2:1 v/v) solvent with/without addition of BHA, and then stored at $30^{\circ}C$. The deterioration of oil was examined periodically by measuring acid value(AV), peroxide value(POV), carbonyl value(COV), and oxygen absorption. The changes in fatty acid composition during the storage was determined by GLC analysis to elucidate the oxidative stability of individual fatty acid. Formation of free fatty acid increased rapidly according to the storage time elapsed in the BHA free oil while it was obviously inhibited in the BHA added oil. Peroxides and carbonyl compounds were formed very rapidly at the beginning of storage of BHA free oil. But in the oil extracted with BHA, formation of peroxides was somewhat inhibited and formation of carbonyl compounds was very strongly inhibited. Principal fatty acids of sardine oil were $C_{16:0},\;C_{16:1},\;C_{18:1},\;C_{20:5}\;and\;C_{22:6}$ acids, and $\omega_33$ polyunsaturated fatty acid $(\omega_3\;PUFA)$ content was very high as much as $23\%$ of the total fatty acid content. The oxidative degradation of fatty acids was enhanced at PUFA especially $C_{20:5}$ ana $C_{22:6}$ acid in BHA free oil. However, the oxidation was fairly retarded in the oil extracted with BHA and the both $C_{20:5}$ and $C_{22:6}$ acids remained at the end of a month storage.