• Bulletin of the Korean Chemical Society
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• v.11 no.2
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• pp.105-108
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• 1990

A spectroelectrochemical study on the redox chemistry of polyaniline (PANI) was carried out by using indium-tin oxide (ITO) transparent electrode in aqueous acidic solutions. Three different PANI-derived species were observed depending on the potential. The most highly oxidized species having alternating benzenoid-quinoid structures degraded through hydrolysis reaction. The degradation products were confirmed to be p-benzoquinone (BQ) and p-diaminobenzene (PDAB) by spectrophotometry anld potentiostatic experiments. Finally, a degradation mechanism is deduced from the observed behaviour.

• Proceedings of the Korean Biophysical Society Conference
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• 1997.07a
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• pp.15-15
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• 1997

Recent studies indicate that hydrogen peroxide (H$_2$O$_2$), which is one of the reactive oxygen species involved in the oxidative stress, is an intracellular secondary messenger in the signal transduction. A novel family of thiol specific antioxidant (TSA) enzymes with a peroxidase activity shows no sequence homology to previously known antioxidant enzymes.(omitted)

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.268.1-268.1
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• 2003

Brazilin is the phenolic compound isolated from the Caesalpinia sappan. This compound has shown a wide range of physiological properties, such as hypoglycemic, anticonvulsant, vasorelaxing, and immunomodulating effects. In this study, we have found that brazilin induced DNA strand scissions in the presence of Cu(II) and this DNA cleavages were mediated by reactive oxygen species. (omitted)

• Molecules and Cells
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• v.45 no.11
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• pp.781-788
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• 2022

Proline plays a multifaceted role in protein synthesis, redox balance, cell fate regulation, brain development, and other cellular and physiological processes. Here, we focus our review on proline metabolism in neurons, highlighting the role of dysregulated proline metabolism in neuronal dysfunction and consequently neurological and psychiatric disorders. We will discuss the association between genetic and protein function of enzymes in the proline pathway and the development of neurological and psychiatric disorders. We will conclude with a potential mechanism of proline metabolism in neuronal function and mental health.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.4
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• pp.443-450
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• 2011

The three-reactor chemical-looping process (TRCL) for the production of hydrogen from natural gas is attractive for both $CO_2$ capture and hydrogen production. In this study, redox property of $Fe_2O_3$ and $WO_3$ supported with $ZrO_2$ and $MgAl_2O_4$ were studied with temperature programmed oxidation/reduction (TPO/R) experiment. All metal oxides were prepared by ball mill method. Metal oxides supported with $ZrO_2$ showed the good redox property in TPO and TPR tests. Reduction behavior was matched well the theoretical reduction mechanism. Metal oxides supported with $MgAl_2O_4$ formed a solid solution ($MgFe_{0.6}Al_{1.4}O_4$, $MgWO_4$). $Fe_2O_3$ showed more narrow reaction range and lower reaction temperature than $WO_3$.

• Proceedings of the Botanical Society of Korea Conference
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• 1999.07a
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• pp.57-62
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• 1999

Light-regulated translation of chloroplast mRNAs requires nuclear-encoded trans-acting factors that interact with the 5' untranslated region (UTR) of these mRNAs. A set of four proteins (60, 55, 47, and 38 kDa) that bind to the 5'-UTR of the psbA mRNA had been identified in C. reinhardtii. 47 kDa protein (RB47) was found to encode a chloroplast poly (A)-binding protein (cPABP) that specifically binds to the 5'-UTR of the psbA mRNA, and essential for translation of this mRNA, cDNA encoding 60 kDa protein (RB60) was isolated, and the amino acid sequence of the encoded protein was highly homologous to plants and mammalian protein disulfide isomerases (PDI), normally found in the endoplasmic reticulum (ER). Immunoblot analysis of C. reinhardtii proteins showed that anti-PDI recognized a distinct protein of 56 kDa in whole cell extract, whereas anti-rRB60 detected a 60 kDa protein. The ER-PDI was not retained on heparin-agarose resin whereas RB60 was retained. In vitro translation products of the RB60 cDNA can be transported into C. reinhardtii chloroplast in vitro. Immunoblot analysis of isolated pea chloroplasts indicated that higher plant also possess a RB60 homolog. In vitro RNA-binding studies showed that RB60 modulates the binding of cPABP to the 5'-UTR of the psbA mRNA by reversibly changing the redox status of cPABP using redox potential or ADP-dependent phosphorylation. Site-directed mutagenesis of -CGHC- catalytic site in thioredoxin-like domain of RB60 is an unique PDI located in the chloroplast of C. reinhardtii, and suggest that the chloroplast PDI may have evolved to utilize the redox-regulated thioredoxin like domain as a mechanism for regulating the light-activated translation of the psbA mRNA.

• Proceedings of the Botanical Society of Korea Conference
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• 1985.08b
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• pp.7-18
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• 1985

Light-regulated translation of chloroplast mRNAs requires nuclear-encoded trans-acting factors that interact with the 5' untranslated region (UTR) of these mRNAs. A set of four proteins (60, 55, 47, and 38 kDa) that bind to the 5'-UTR of the psbA mRNA had been identified in C. reinhardtii. 47 kDa protein (RB47) was found to encode a chloroplast poly (A)-binding protein (cPABP) that specifically binds to the 5'-UTR of the psbA mRNA, and essential for translation of this mRNA, cDNA encoding 60 kDa protein (RB60) was isolated, and the amino acid sequence of the encoded protein was highly homologous to plants and mammalian protein disulfide isomerases (PDI), normally found in the endoplasmic reticulum (ER). Immunoblot analysis of C. reinhardtii proteins showed that anti-PDI recognized a distinct protein of 56 kDa in whole cell extract, whereas anti-rRB60 detected a 60 kDa protein. The ER-PDI was not retained on heparin-agarose resin whereas RB60 was retained. In vitro translation products of the RB60 cDNA can be transported into C. reinhardtii chloroplast in vitro. Immunoblot analysis of isolated pea chloroplasts indicated that higher plant also possess a RB60 homolog. In vitro RNA-binding studies showed that RB60 modulates the binding of cPABP to the 5'-UTR of the psbA mRNA by reversibly changing the redox status of cPABP using redox potential or ADP-dependent phosphorylation. Site-directed mutagenesis of -CGHC- catalytic site in thioredoxin-like domain of RB60 is an unique PDI located in the chloroplast of C. reinhardtii, and suggest that the chloroplast PDI may have evolved to utilize the redox-regulated thioredoxin like domain as a mechanism for regulating the light-activated translation of the psbA mRNA.

• Applied Chemistry for Engineering
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• v.31 no.3
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• pp.299-304
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• 2020

Nanoparticles play an important role as a catalyst in many chemical syntheses. Colloidal nanoparticles were usually synthesized with reducing, capping, and shape directing agents which induce surface poisoning of catalysts. A new green synthesis for silver nanoparticles was developed by utilizing less additives which could be a hazardous waste. A crystallization technique was employed to reduce the amount of reducing and capping agents during synthesis resulting in less surface poisoning of the nanoparticle. The synthesized Ag nanoparticles using monosaccharides and disaccharides as reducing agents could be used as a catalyst for the redox reaction of resazurin and the mechanism of the reaction using Ag nanoparticles was studied.

• Applied Chemistry for Engineering
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• v.5 no.4
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• pp.580-587
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• 1994

The oxidative coupling of methane was studied kinetically using $Na^+(50wt%)/MgO$ catalyst at 710, 730, 750, 770 and $790^{\circ}C$ in a fixed bed flow reactor at the atmospheric pressure under differential conversion conditions. Through curve fitting, it was found that the Langmuir-Hinshelwood type mechanism was fitted to this reaction rather than Rideal-Redox type or Eley-Rideal type mechanism. Therefore, it was proposed that the $O_2{^-}$ or $O_2{^{2-}}$ species on the surface was related to the production of $CH_3{\cdot}$. The estimated activation energy of $CH_3{\cdot}$ production was about 39.3kcal/mol. Moreover, as the result of curve fitting, the stoichiometric coefficient of $O_2$ for the production of $CH_3{\cdot}$ to produce $CO_x$was approximately 1.5. Accordingly, it could be concluded that the $CH_3O_2{\cdot}*$ was prouduced through the partial oxidation of $CH_3{\cdot}$ with the surface oxygen.

• The Journal of Korean Obstetrics and Gynecology
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• v.19 no.1
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• pp.97-110
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• 2006

Purpose : To address the ability of Myrrha (MY) to induce cell death, we investigated the effect of MY on apoptosis. In human cervical carcinoma HeLa cells, apoptosis occurred following MY exposure in a dose-dependent manner. Methods : We have tested several kinds of anti-oxidants to investigate the MY-induced apoptotic mechanism. Among the anti-oxidants, N-acetyl cysteine(NAC) or reduced glutathione (GSH) protects MY-induced apoptosis. NAC is an aminothiol and synthetic precursor of intracellular cysteine and GSH. To confirm the role of GSH in MY-induced apoptosis, methionine and cystathionine-glutathione extrusion inhibitors were treated in the presence of MY. Results : NAC, GSH, methionine or cystathionine led to protective effect against MY-induced apoptosis in HeLa cells. The GSH and GSH-associated reagents regulate MY-induced cytochrome c release and the resultant caspase-3 activation. Furthermore, the two specific inhibitors of carrier-mediated GSH extrusion, methionine and cystathionine demonstrate GSH extrusion occurs via a specific mechanism. While decreasing GSH extrusion and protecting against MY-induced apoptosis, methionine and cystathionine failed to exert anti-apoptotic activity in cells previously deprived of GSH. Conclusion : the target of the protection is indeed GSH extrusion. This shows that the protective effect is achieved by forcing GSH to stay within the cells during apoptogenic treatment. All this evidence indicates the extrusion of GSH precedes andis responsible for the apoptosis, probably by altering the intracellular redox state, thus giving a rationale for the development of redox-dependent apoptosis in MY-treated human cervical carcinoma HeLa cells.