• Applied Biological Chemistry
• /
• v.30 no.3
• /
• pp.219-226
• /
• 1987

Peroxidase isozyme C was isolated from mung bean cotyledon and purified to homogeneity as ascertained by chromatography and polyacrylamide gel electrophoresis, and then crystallized. Purification procedures included ammonium sulfate precipitation and column chromatography on Sephadex G-75, DEAE-cellulose and DEAE-Sephadex A-50. Peroxidase isozyme C was purified about 63 fold with 5% recovery. Isozyme C showed optimal activity at pH 5.0 with o-dianisidine and at pH 6.0 with guaiacol as substrate, and the optimal temperature was $70^{\circ}C$. Molecular weight of 50,000 was estimated for the isozyme C by SDS-polyacrylamide gel electrophoresis. At $70^{\circ}C$, it took 30 min to inactivate the isozyme to 50%, and at $80^{\circ}C$, this isozyme was almost completely inactivated in 20 min. The Km value of isozyme C for o-dianisidine was 0.11mM and that for guaiacol was 60.98mM using hydrogen peroxide as cosubstrate, and the kinetic pattern showed a competitive cyanide inhibition with respect to substrate. The crystalline structure of isozyme C was rectangular in shape.

• Korean Journal of Environmental Agriculture
• /
• v.18 no.3
• /
• pp.292-297
• /
• 1999

This study was performed to estimate the possibility of use of plant materials as catalytic agents fur the decontamination of waste waters contaminated with organic pollutants by using 2,4-dichlorophenol(2,4-DCP) as a model pollutant. Plant materials containing high peroxidase activity were selected as catalysts for the removal of 2,4-DCP. Peroxidase activity, which plant materials were containing, was measured, and the greatest peroxidase activity was observed in shepherd's purse, followed by turnip, sweet potato, Chinese cabbage and white radish. The peroxidase activity in shepherd's purse was four times higher than that of horseradish purchased in U.S.A. Using shepherd' s purse and turnip, it was investigated the effect of various factors on the decontamination of 2,4-DCP through oxidative coupling. The removal of 2,4-DCP was extremely fast, and a maximal removal could be achieved within 3 min for shepherd' s purse and 15min for turnip. The pH range was from 3.0 to 8.0 and the amount of $H_2O_2$ added was 9mM when maximal removal was achieved(over 90%). No increasing removal of 2,4-DCP was observed due to increasing the amount of $H_2O_2$ added (over 9mM). The initial concentration affected the transformation of 2,4-DCP incubated with plant materials. When turnip was used as catalytic agent, it was observed decreasing transformation of 2,4-DCP due to increasing initial concentration.

• Analytical Science and Technology
• /
• v.19 no.6
• /
• pp.482-489
• /
• 2006

Two electrode-based lactate biosensor was prepared by immobilizing lactate oxidase (LOD) obtained from pediococcus species in a poly(vinyl alcohol). Hydrogen peroxide ($H_2O_2$) produced by the reaction of lactate and LOD was detected on the Pt-black that was electrochemically deposited on the Au electrode. Sensors fabricated with Pt-black deposited Au electrode provided a high current of $H_2O_2$ oxidation at a substantially lowered applied potential (+300 mV vs. Ag/AgCl), resulting in reduced interferences from easily oxidizable species such as ascorbic acid, acetaminophen, and uric acid. An outer membrane is formulated by adjusting water uptake of hydrophilic polyurethane (HPU). The sensor performance was evaluated in vitro with both flow-through arrangement and static mode. The sensor showed a linear range from 0.1 mM to about 9.0 mM in 0.05 M phosphate buffer (pH 7.6) containing 0.05 M NaCl. Storing the sensors prepared in this work at $4^{\circ}C$ buffer solution while not in use, they provided same electrochemical performance for more than 25 days.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.35 no.8
• /
• pp.979-984
• /
• 2006

Although iron is essential for many physiological processes, excess iron can lead to tissue damage by promoting the generation of reactive oxygen species (ROS). There is increasing evidence that ROS might play an important role in the pathogenesis of cardiovascular disease. However, the effects of iron excess on platelet function and the thrombotic response to vascular injury are not well understood. We examined the effects of iron excess-induced oxidative stress and the antioxidants on platelet aggregation. Oxidative stress was accessed by either free iron $(Fe^{+2})$ or hydrogen peroxide $(H_2O_2)$, as well as their combination on washed rabbit platelets (WPs) in vitro. When WPs were stimulated with either $Fe^{+2}$ alone or a subthreshold concentration of collagen, which gave an aggregatory curve with a little effect, and a dose dependent increase in platelet aggregation was observed by increasing concentrations of $Fe^{+2}$ with $H_2O_2$. This aggregation was associated with the iron-catalyzed formation of hydroxyl radicals from $H_2O_2$, and were inhibited by NAD/NADP (proton acceptor), catalase $(H_2O_2\;scavenger)$, tiron (iron chelator), mannitol (hydroxyl radical scavenger), and indomethacin (cyclooxygenase inhibitor), but not by NADH/NADPH (proton donor), superoxide mutase, and aspirin. However, NADH/NADPH, an essential cofactor for the antioxidant capacity by the supply of reducing potentials, showed the effect of an enhanced radical formation, suggesting a role for NADH/NADPH-dependent oxidase. These results suggest that iron $(Fe^{+2})$ can directly interact with washed rabbit platelets and this aggregation be mediated by OH formation as in the Fenton reaction, inhibited by radical scavengers.

• Korean Journal of Food Science and Technology
• /
• v.46 no.3
• /
• pp.369-374
• /
• 2014

The physiological characteristics of kiwi (Actinidia delicosa) fruit were analyzed, which inclued its nutritional composition, in vitro-antioxidant activities, and neuronal cell protective effects. The most abundant components of mineral, amino acid, and fatty acid were found to be potassium (K), glutamic acid, and a-linolenic acid, respectively. The major free sugars were fructose, glucose, and sucrose. In addition, ${\beta}$-carotene and vitamin C contents were $1.35{\mu}g/100mL$ and 29.21 mg/100 g, respectively. The 2,2'-azinobis-(3-ethylbenothiazline-6-sulfonic acid) (ABTS) radical-scavenging activity of the n-hexane fraction obtained from the kiwi extract was 10.52% at a concentration of $1000{\mu}g/mL$. The malondialdehyde (MDA) inhibition of the n-hexane fraction was found to increased in a dose-dependent manner. The intracellular reactive oxygen species (ROS) accumulation after hydrogen peroxide ($H_2O_2$) treatment of PC12 cells was significantly reduced in the presence of the n-hexane fraction compared to PC12 cells treated with $H_2O_2$ only. Moreover, in the a MTT assay, the n-hexane fraction showed in vitro-protective effects against $H_2O_2$-induced neurotoxicity.

• Tuberculosis and Respiratory Diseases
• /
• v.59 no.1
• /
• pp.30-38
• /
• 2005

Background : Arsenic trioxide ($As_2O_3$) has been used to treat acute promyelocytic leukemia, and it induces apoptosis in a variety of solid tumor cell lines including non-small cell lung cancer cells. However, nonsteroidal antiinflammatory drugs (NSAID) can enhance tumor response to chemotherapeutic drugs or radiation. It was previously demonstrated that a combination treatment with $As_2O_3$ and sulindac induces the apoptosis of NCI-H157 human lung carcinoma cells by activating the caspase cascade. This study aimed to determine if a combination treatment augmented its apoptotic potential through other pathways except for the activation of the caspase cascade. Material and Methods : The NCI-H157 cells were treated with $As_2O_3$, sulindac and antioxidants such as glutathione (GSH) and N-acetylcysteine (NAC). The cell viability was measured by a MTT assay, and the level of intracellular hydrogen peroxide ($H_2O_2$) generation was monitored fluorimetrically using a scopoletin-horse radish peroxidase (HRP) assay. Western blotting and mitochondrial membrane potential transition analysis were performed in order to define the mechanical basis of apoptosis. Results : The viability of the cells was decreased by a combination treatment of $As_2O_3$ and sulindac, and the cells were protected using antioxidants in a dose-dependent manner. The increased $H_2O_2$ generation by the combination treatment was inhibited by antioxidants. The combination treatment induced changes in the mitochondrial transmembrane potential as well as the expression of the Bcl-2 family proteins, and increased cytochrome c release into the cytosol. However, the antioxidants inhibited the effects of the combination treatment. Conclusion : Combination treatment with $As_2O_3$ and sulindac induces apoptosis in NCI-H157 human lung carcinoma cells via ROS generation with a mitochondrial dysfunction.

• Journal of Korean Society of Environmental Engineers
• /
• v.31 no.10
• /
• pp.873-882
• /
• 2009

Sonolysis of TCE (Trichloroethylene) was performed in 584 kHz rectangular reactor. At first, the effect of acoustic power and aqueous temperature which are both important factors to operate ultrasound system on sonolysis of TCE were examined under one side irradiation condition. First degradation rate constants of TCE and chloride yields were increased with increasing acoustic power from 100 to 300 W. And increasing the aqeuous temperature resulted in the increase of first degradation rate constants of TCE and the decrease of chloride yield. Sonolysis of TCE was performed under multi ultrasound irradiation conditions that total acoustic power of 300 W was distributed according to the number of irradiation sides. First degradation rate constants of TCE followed the order 4 sides > 3 sides > 1 side > 2 sides (parallel) > 2 sides (orthogonal). When comparing the experimental results under parallel and orthogonal irradiation conditions of 2 sides with 300 and 450 W, first degradation rate constants of TCE were similar, while production rate constants of hydrogen peroxide were more higher at parallel conditions compared to orthogonal conditions.

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.4
• /
• pp.765-773
• /
• 2000

The degradation of humic acid using $TiO_2$ coatings was studied, $TiO_2$ coatings were prepared by dip-coating method. Sol solutions for coating were prepared by mixing the gel, which can be produced by the reaction of $TiOCl_2$ and $NH_4OH$ solution, and hydrogen peroxide solution, and hydrolysis of titanium tetraisopropoxide (TTIP). It was shown from XRD that coatings from sol aged at $100^{\circ}C$ for 18h with titanium peroxo solution were crystallized to anatase in the range of temperatures of $25^{\circ}C$ to $500^{\circ}C$. In contrast, those coated from TTIP were crystallized to anatase at temperature above $400^{\circ}C$. So the sols originated from $TiCl_4$ can be applied for not only on the heat-resistance substrates but on the plastic substrates. Thickness and the quality of the films were dependent on the withdrawing speed, the concentration of sol, and the number of coating. The films showed various interference colors depending on the thickness of them. In the case that the films coated 2 times at withdrawing speed of 2.5cm per minute by 0.2M sol, the films had a transparent light blue color with thickness of around 50nm. It was known from the result of photo-degradation by $TiO_2$ coatings using humic acid that the removal efficiency of $COD_{cr}$ was over 85% after illumination of $UV/H_2O_2$ for 40min. and that of UV/VIS absorbable materials was over 95%.

• Journal of Life Science
• /
• v.31 no.2
• /
• pp.126-136
• /
• 2021

Oxidative stress causes injury to and degeneration of retinal pigment epithelial (RPE) cells. It is involved in several retinal disorders and leads to vision loss. In the present study, we investigated the effect of 14 kinds of natural compounds and two kinds of synthetic compounds on oxidative stress-induced cellular damage in human PRE cell lines (ARPE-19). From among them, we selected five kinds of compounds, including auranofin, FK-509, hemistepsin A, honokiol, and spermidine, which have inhibitory effects against hydrogen peroxide (H2O2)-mediated cytotoxicity. In addition, we found that four kinds of compounds (excluding auranofin) have protective effects on H2O2-induced mitochondrial dysfunction. Furthermore, the expression of phosphorylation of histone H2AX, a sensitive marker of DNA damage, was markedly up-regulated by H2O2, whereas it was notably down-regulated by FK-506, honokiol, and spermidine treatment. Meanwhile, five kinds of candidate compounds had no effect on H2O2-induced intracellular reactive oxygen species (ROS) levels, suggesting that the five candidate compounds have protective effects on oxidative stress-induced cellular damage through the ROS-independent pathway. Taken together, according to the results of H2O2-mediated cellular damage―such as cytotoxicity, apoptosis, mitochondrial dysfunction, and DNA damage―spermidine and FK-506 are the natural and synthetic compounds with the most protective effects against oxidative stress in RPE. Although further studies on the identification of the mechanism responsible are required, the results of the present study suggest the possibility of using spermidine and FK-506 to suppress the risk of retinal disorders.

• Animal Bioscience
• /
• v.34 no.10
• /
• pp.1590-1599
• /
• 2021

Objective: This study investigates the expression patterns of toll-like receptors (TLRs) and intracellular mediators in horse muscle cells after exercise, and the relationship between TLRS expression in stressed horse muscle cells and immune cell migration toward them. Methods: The expression patterns of the TLRs (TLR2, TLR4, and TLR8) and downstream signaling pathway-related genes (myeloid differentiation primary response 88 [MYD88]; activating transcription factor 3 [ATF3]) are examined in horse tissues, and horse peripheral blood mononuclear cells (PBMCs), polymorphonuclear cells (PMNs) and muscles in response to exercise, using the quantitative reverse transcription-polymerase chain reaction (qPCR). Expressions of chemokine receptor genes, i.e., C-X-C motif chemokine receptor 2 (CXCR2) and C-C motif chemokine receptor 5 (CCR5), are studied in PBMCs and PMNs. A horse muscle cell line is developed by transfecting SV-T antigen into fetal muscle cells, followed by examination of muscle-specific genes. Horse muscle cells are treated with stressors, i.e., cortisol, hydrogen peroxide (H₂O₂), and heat, to mimic stress conditions in vitro, and the expression of TLR4 and TLR8 are examined in stressed muscle cells, in addition to migration activity of PBMCs toward stressed muscle cells. Results: The qPCR revealed that TLR4 message was expressed in cerebrum, cerebellum, thymus, lung, liver, kidney, and muscle, whereas TLR8 expressed in thymus, lung, and kidney, while TLR2 expressed in thymus, lung, and kidney. Expressions of TLRs, i.e., TLR4 and TLR8, and mediators, i.e., MYD88 and ATF3, were upregulated in muscle, PBMCs and PMNs in response to exercise. Expressions of CXCR2 and CCR5 were also upregulated in PBMCs and PMNs after exercise. In the muscle cell line, TLR4 and TLR8 expressions were upregulated when cells were treated with stressors such as cortisol, H₂O₂, and heat. Migration of PBMCs toward stressed muscle cells was increased by exercise and oxidative stresses, and combinations of these. Treatment with methylsulfonylmethane (MSM), an antioxidant on stressed muscle cells, reduced migration of PBMCs toward stressed muscle cells. Conclusion: In this study, we have successfully cultured horse skeletal muscle cells, isolated horse PBMCs, and established an in vitro system for studying stress-related gene expressions and function. Expression of TLR4, TLR8, CXCR2, and CCR5 in horse muscle cells was higher in response to stressors such as cortisol, H₂O₂, and heat, or combinations of these. In addition, migration of PBMCs toward muscle cells was increased when muscle cells were under stress, but inhibition of reactive oxygen species by MSM modulated migratory activity of PBMCs to stressed muscle cells. Further study is necessary to investigate the biological function(s) of the TLR gene family in horse muscle cells.