• Journal of Nutrition and Health
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• v.30 no.9
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• pp.1061-1066
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• 1997

This study was undertaken to evaluate the effect of 4 weeks of $\alpha$-tocopherol(800 I.U./d) supplementation on oxidant stress of eleven female aerobic -majoring students during rest and exercise. Changes in the activity of the antioxidant enzyme glutathione peroxidase were also studied. Serum $\alpha$-tocopherol concentration was significantly increased with vitamin E supplementation(710.1$\pm$113.8$\mu\textrm{g}$/dl vs. 1,485,8$\pm$105.2$\mu\textrm{g}$/dl). In addition, serum MDA concentration, an index of lipid peroxidation, significantly decreased after vitamin E supplementation. However, MDA values after exercise increased to pre-supplementation levels. Serum glutathione peroxidase activity significantly increased with vitamin E supplementation. The enzyme activity showed a trend toward decrease after exercise. Serum cholesterol values were not significantly affected by vitamin E supplementation. However, serum triglycerides significantly increased after supplementation against oxidative stress during resting periods. These supplements appraently work by decreasing lipid peroxidation and increasing glutathione peroxidase activity. However, vitamin E supplementation did not prevent exercise-induced increases in lipid peroxidation.

• Korean Journal of Veterinary Research
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• v.31 no.1
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• pp.41-47
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• 1991

The protective of influences of sodium selenitc ($Na_2SeO_3$) against the methemoglobinemia with sodium nitrite were investigated on hemoglobin, methemoglobin, glutathione peroxidase and NADH-methemoglobin reductase activity in rabbits which were given 0,1,3 and 9ppm sodium selenite of drinking water for a week. Dietary selenium did not alter total hemoglobin in the blood of rabbits. Selenium was found to decrease nitrite-induced methemoglobin in a dose-dependent manner. The glutathione peroxidase activity was also increased by selenium in all the experimental groups. However, the NADH-methemoglobin reductase activity by selenite did not show significant differences as concerns the methemoglobinemia. These results showed that selenium could inhibit nitrite-induced methemoglobinemia. Its influence of inhibition is suggested that the effect of the reduction of methemoglobin was greatly stimulated by glutathione peroxidase activity.

• Korean Journal of Veterinary Research
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• v.30 no.3
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• pp.271-275
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• 1990

The tests related to red cell fragility were performed. Samples of blood anticoagulated with heparin were obtained from Korean native cattle in Chonbuk region abattoir, and classified by the district(Kun) with reference to breeding location. Hemolysis test for red cell fragility was performed with whole blood and glutathione peroxidase activity was measured spectrophotometrically. Blood concentration of selenium, inorganic component of glutathione peroxidase, was also determined fluorophotometrically. The results obtained were summerized as follows; 1. Percent hemolysis of erythrocytes ranged from 13.53 to 20.74%, and its mean Palue was low as $17.11{\pm}9.91%$. Means in all were not district(Kun) in Chonbuk region significantly different. 2. Glutathione peroxidase activity ranged from 2,881 to 4,000mU/ml, and high mean values, $3,352{\pm}1,872mU/ml$, reflected low percent hemolysis. 3. There was a highly negative correlation between the red cell fragility(Y) and blood glutathione peroxidase activity(X). The linear regression equation for these data was: Y=29.86-3.75X with a correlation coefficient of r=-.6886 (p<0.01) 4. Blood selenium concentration ranged from 0.16 to $0.24{\mu}g/ml$, and mean values was normal level as $0.2{\pm}0.11{\mu}g/ml$. 5. There was a highly positive correlation between blood selenium concentration(X), and blood glutathione peroxidase activity(Y). The linear regression for these data was: Y=230+15,790X, with a correlation coefficient officient of r=0. 8635.

• Korean Journal of Veterinary Service
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• v.30 no.3
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• pp.291-304
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• 2007

Mutants of an obligate aerobic bacterium, Vitreoscilla, that have deficiency in heat-labile catalase-peroxidase hydroperoxidase I (HPI) were created by EMS treatment. The catalase-peroxidase HPI-deficient mutant showed substantially lower peroxidase activity in exponential and mid-stationary phase compared with the wild type strain. In late stationary phase, the mutant exhibited no peroxidase activity. Peroxidase deficiency in the mutant was revealed by polyacrylamide gels stained for peroxidase activity. Characteristically, catalase levels in the mutant increased about 14- and 8-fold during growth in the exponential and stationary phases, respectively, compared to those in the wild type, suggesting a compensatory effect for protection from $H_2O_2$ toxicity. The mutant showed differences in physiology from the wild type: retardation in growth rate and decrease in oxygen consumption. Both the wild type and the catalase-peroxidase HPI-deficient mutant of Vitreoscilla had lower growth rates in media containing increasing $H_2O_2$ concentrations. However, the mutant exhibited an additionally decreased growth rate after 6 to 8 h of growth compared to the wild type. The wild type was resistent up to 20 mM $H_2O_2$, whereas the mutant was very sensitive to high concentrations of exogenous $H_2O_2$. Although elevated catalase levels would provide protection of the bacteria from the deleterious effect of $H_2O_2$, it did not appear to be complete. Cell-free extracts of the mutant showed decreased NADH oxidation rates and higher accumulation of $H_2O_2$ during this oxidation. These results may account for the impaired growth and earlier onset of death phase by the catalase-peroxidase HPI-deficient mutant of Vitreoscilla.

• Current Research on Agriculture and Life Sciences
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• v.10
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• pp.99-108
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• 1992

This experiment was conducted to investigate biological activity of ABA and its analogues on barley shoot growth and peroxidase activity in barley seedlings. The treatments of 3.2 ppm (+)-ABA, 1.2 ppm (S)-(+)-ABA, 0.6 ppm ABA-methyl cinnamate ester compound (AC), and 0.08 ppm ABA-umbelliferone ester compound (AU) inhibited the growth of barley seedlings by more than 80% as compared with untreated control. The increase in barley shoot-inhibit activity of (S)-(+)-ABA became 3-fold than the activity of racemic ABA, and those of AC and AU higher than that of (S)-(+)-ABA by about 2.5 and 16 times, respectively. Peroxidase activities of barley shoots during the early growth stage were kept at a constant levels without ABA treatment, but in the treatment of racemic ABA, (S)-(+)-ABA, AC and AU increased the activities. Furthermore, the peroxidase activities increased as the higher concentration of ABA and its analogues were applied.

• Journal of Microbiology and Biotechnology
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• v.19 no.9
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• pp.966-971
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• 2009

Peroxidase from Coprinus cinereus (CiP) has attracted attention for its high specific activity and broad substrate spectrum compared with other peroxidases. In this study, the functional expression of this peroxidase was successfully achieved in the methylotrophic yeast Pichia pastoris. The expression level of CiP was increased by varying the microbial hosts and the expression promoters. Since a signal sequence, such as the alpha mating factor of Saccharomyces cerevisiae, was placed preceding the cDNA of the CiP coding gene, expressed recombinant CiP (rCiP) was secreted into the culture broth. The Mut Pichia pastoris host showed a 3-fold higher peroxidase activity, as well as 2-fold higher growth rate, compared with the $Mut^s $ Pichia pastoris host. Furthermore, the AOX1 promoter facilitated a 5-fold higher expression of rCiP than did the GAP promoter.

• Journal of Plant Biology
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• v.29 no.4
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• pp.233-242
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• 1986

In order to pursue some physiological studies on organogenesis in ginseng tissue culture, ginseng root explants were cultured on a modified MS medium containing NAA and kinetin. The activities of peroxidase and some enzymes were investigated and their isoenzyme patterns were also observed. The activity of peroxidase decreased by 20% in one week's culture and increased thereafter by 80% in culturing for 7 weeks compared with the control group. Glucose-6-phosphate dehydrogenase activity increased by 400% after culturing for 5 weeks and increased during the days preceeding root formation. The activities of glutamate dehydrogenase and acid phosphatase also increased during the culture. After 3 weeks' culture, new peroxidase isozyme (pH 7.6) appeared and 7 weeks' culture, another new peroxidase isozyme (pH unidentified) appeared. These patterns were also identified by using FPLC. After 7 weeks' culture, a new esterase isozyme of pH 8.5 appeared and isozyme patterns of acid phosphatase were quite changed compared with the isozyme patterns of tissue cultured for 5 weeks. In so far as these new isoenzymes appear distinctively after 7 weeks' culture, root differentiation is supposed to be induced after 7 weeks' culture.

• Carbon letters
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• v.24
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• pp.103-110
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• 2017

Carbon-based magnetic nanostructures in several instances have resulted in improved physicochemical and catalytic properties when compared to multi-wall carbon nanotubes (MWCNTs) and magnetic nanoparticles. In this study, magnetic MWCNTs with a structure of $Ni_xZn_xFe_2O_4/MWCNT$ as peroxidase mimics were fabricated by the one-pot hydrothermal method. The structure, composition and morphology of the nanocomposites were characterized with X-ray diffraction (XRD), Fourier transform infrared spectroscopy and transmission electron microscopy. The magnetic properties were investigated with a vibrating sample magnetometer. The peroxidase-like catalytic activity of the nanocomposites was investigated by colorimetric and electrochemical tests with 3,3',5,5'-tetramethylbenzidine (TMB) and $H_2O_2$ as the substrates. The results show that the synthesis of the nanocomposites was successfully performed. XRD analysis confirmed the crystalline structures of the $Ni_xZn_xFe_2O_4/MWCNT$ nanohybrids and MWCNTs. The main peaks of the $Ni_xZn_xFe_2O_4/MWCNT$s crystals were presented. The $Ni_{0.25}Zn_{0.25}Fe_2O_4/MWCNT$ and $Ni_{0.5}Zn_{0.5}Fe_2O_4/MWCNT$ nanocatalysts showed nearly similar physicochemical properties, but the $Ni_{0.5}Zn_{0.5}Fe_2O_4/MWCNT$ nanocatalyst was more appropriate than the $Ni_{0.25}Zn_{0.25}Fe_2O_4/MWCNT$ nanocatalyst in terms of the magnetic properties and catalytic activity. The optimum peroxidase-like activity of the nanocatalysts was obtained at pH 3.0. The $Ni_{0.5}Zn_{0.5}Fe_2O_4/MWCNT$ nanocatalyst exhibited a good peroxidase-like activity. These magnetic nanocatalysts can be suitable candidates for future enzyme-based applications such as the detection of glucose and $H_2O_2$.

• Journal of Life Science
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• v.33 no.1
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• pp.8-14
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• 2023

Peroxidasin (PXDN), a multidomain heme peroxidase containing extracellular matrix (ECM) motifs, as well as a catalytic domain, catalyzes the sulfilimine crosslink of collagen IV (Col IV) to reinforce Col IV scaffolds. We previously reported that PXDN is required for endothelial cell (EC) survival and growth signaling through sulfilimine crosslink-dependent matrix assembly. In this study, we examined whether peroxidase activity is required for PXDN function in ECs. First, we constructed a mutant PXDN by point mutation of two highly conserved amino acids, Q823 and D826, which are present in the active site of the peroxidase domain. After isolation of HEK293 clones highly expressing the mutant protein, conditioned medium (CM) was obtained after incubating the cells in serum-free medium for 24 hours and then analyzed by Western blot analysis under nonreducing conditions. The results revealed that the mutant PXDN formed a trimer and that it was cleaved by proprotein convertase-like wild-type (WT) PXDN. However, peroxidase activity was not detected in the CM containing the mutant PXDN, in contrast to that of WT PXDN. In addition, the sulfilimine crosslink ability of the mutant PXDN was lost. Moreover, the CM containing the mutant PXDN failed to promote the growth of PXDN-depleted ECs, unlike the CM containing WT PXDN. These results suggest that the peroxidase activity of PXDN affects EC growth by forming a sulfilimine crosslink.

• BMB Reports
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• v.33 no.3
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• pp.234-241
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• 2000

A new type of the human TSA homologous gene was cloned from a HeLa cell cDNA and characterized. The gene product consists of 161 amino acids with a molecular mass of 16,900. The TSA homologous protein, as a new 6th member of the human TSA (hTSA VI), exerted a thioldependent peroxidase activity with the use of thioredoxin system as a physiological electron donor. The values of $V_{max}/K_m$ of hTSA VI for $H_2O_2$ and t-butyl hydroperoxide (t-BOOH) were calculated as $5.53{\times}10^{-2}$ and $3.70{\times}10^{-2}$, respectively. This implies that hTSA VI is a peroxidase, which reduces $H_2O_2$ and t-BOOH. The mutation of $Cys^{47}$ to serine resulted in a complete loss of the peroxidase activity. This suggests that $Cys^{47}$ acts as a primary site of catalysis. The analysis of the tryptic digest derived from hTSA VI revealed that the $Cys^{47}$ exists as a free thiol form. Taken together, these results suggest that the TSA homologous protein is a new type of the human family, which exerts thioredoxin-linked peroxidase activity toward $H_2O_2$ and alkyl hydroperoxide.