• 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.

• Molecules and Cells
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• v.26 no.5
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• pp.427-435
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• 2008

In this review, we discuss the genes and the related signal pathways that regulate aging and longevity by reviewing recent findings of genetic longevity models in rodents in reference to findings with lower organisms. We also paid special attention to the genes and signals mediating the effects of calorie restriction (CR), a powerful intervention that slows the aging process and extends the lifespan in a range of organisms. An evolutionary view emphasizes the roles of nutrient-sensing and neuroendocrine adaptation to food shortage as the mechanisms underlying the effects of CR. Genetic and non-genetic interventions without CR suggest a role for single or combined hormonal signals that partly mediate the effect of CR. Longevity genes fall into two categories, genes relevant to nutrient-sensing systems and those associated with mitochondrial function or redox regulation. In mammals, disrupted or reduced growth hormone (GH)-insulin-like growth factor (IGF)-1 signaling robustly favors longevity. CR also suppresses the GH-IGF-1 axis, indicating the importance of this signal pathway. Surprisingly, there are very few longevity models to evaluate the enhanced anti-oxidative mechanism, while there is substantial evidence supporting the oxidative stress and damage theory of aging. Either increased or reduced mitochondrial function may extend the lifespan. The role of redox regulation and mitochondrial function in CR remains to be elucidated.

• BMB Reports
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• v.35 no.1
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• pp.127-133
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• 2002

Nitrosative stress can prevent or induce apoptosis. It occurs via S-nitrosylation by the interaction of nitric oxide (NO) with the biological thiols of proteins. Cellular redox potential and non-heme iron content determine S-nitrosylation. Apoptotic cell death is inhibited by S-nitrosylation of the redox-sensitive thiol in the catalytic site of caspase family proteases, which play an essential role in the apoptotic signal cascade. Nitrosative stress can also promote apoptosis by the activation of mitochondrial apoptotic pathways, such as the release of cytochrome c, an apoptosis-inducing factor, and endonuclease G from mitochondria, as well as the suppression of NF-${\kappa}B$ activity. In this article we reviewed the mechanisms whereby S-nitrosylation and nitrosative stress regulate the apoptotic signal cascade.

• KSBB Journal
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• v.21 no.1 s.96
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• pp.16-19
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• 2006

Oxidative modification of nucleoside diphosphate kinase (NDPK) is identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometer. The quaternary structure of NDPK appears to be regulated by cross-linking with an oxidant, $H_2O_2$. We compared roles of NDPK in each of wild type and ynk mutant against oxidative stress. Six specific proteins changed by $H_2O_2$ were identified using two-dimensional electrophoretic analysis. YNK regulated several proteins, related to $H_2O_2$ signaling functions. These results suggest that one of the important functions of NDPK is the regulation of cellular redox state.

• Molecules and Cells
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• v.39 no.1
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• pp.60-64
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• 2016

Inflammation is a pathophysiological response to infection or tissue damage during which high levels of reactive oxygen and nitrogen species are produced by phagocytes to kill microorganisms. Reactive oxygen and nitrogen species serve also in the complex regulation of inflammatory processes. Recently, it has been proposed that peroxiredoxins may play key roles in innate immunity and inflammation. Indeed, peroxiredoxins are evolutionarily conserved peroxidases able to reduce, with high rate constants, hydrogen peroxide, alkyl hydroperoxides and peroxynitrite which are generated during inflammation. In this minireview, we point out different possible roles of peroxiredoxins during inflammatory processes such as cytoprotective enzymes against oxidative stress, modulators of redox signaling, and extracellular pathogen- or damage-associated molecular patterns. A better understanding of peroxiredoxin functions in inflammation could lead to the discovery of new therapeutic targets.

• Archives of Pharmacal Research
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• v.25 no.4
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• pp.485-492
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• 2002

The molecular fate of thyroglobulin (Tg) is controlled by oligomerization, a means of storing Tg at high concentrations, and deoligomerization. The oligomerization of bovine Tg are intermolecular reactions that occur through oxidative processes, such as disulfide and dityrosine formation, as well as isopeptide formation; disulfide formation is primarily responsible for Tg oligomerization. Here, the protein disulfide isomerase (PDI) and/or peroxidase-induced oligomerization of unfolded thyroglobulins, which were prepared by treating bovine Tg with heat, urea or thiol/urea, was investigated using SDS-PAGE analyses. In addition, the enzymatic oligomerization was compared with non-enzymatic oligomerization. The thermally-induced oilgomerization of Tg, dependent on glutathione redox state, was affected by the ionic strength or the presence of a surfactant. Meanwhile, PDI-catalyzed oligomerization, time and pH-dependent, was the most remarkable with unfolded/reduced Tg, which was prepared from a treatment with urea/DTT, while the thermally-unfolded Tg was less sensitive. Similarly, the oligomerization of unfolded/reduced Tg was also mediated by peroxidase. However, PDI showed no remarkable effect on the peroxidase-mediated oligomerization of either the unfolded or unfolded/reduced Tg. Additionally, the reductive deoligomerization of oligomeric Tg was exerted by PDI in an excessively reducing state. Based on these results, it is proposed that PDI catalyzes the oligomerization of Tg through the disulfide linkage and its deoligomerization in the molecular fate, and this process may require a specific molecular form of Tg, optimally unfolded/reduced, in a proper redox state.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.7
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• pp.1151-1160
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• 2016

In recent years, the energy storage systems such as LiB, NaS, RFB(Redox-Flow Battery), Super- capacitor, pumped hydro storage, flywheel, CAES(Compressed Air Energy Storage) and so on have received great attention as practical solutions for the power supply problems. They can be used for various purpose of peak shaving, load leveling and frequency regulation, according to the characteristics of each ESS(energy storage system). This paper will focus at 1 MWh RFB system, which is being developed through the original technology project of energy material. The output of ESS is mainly characterized by C-rate, which means that the total rated capacity of battery will be delivered in 1 hour. And it is a very important factor in the ESS operation scheduling. There can be several options according to the operation intervals 15, 30 and 60minutes. The operation scheduling is based on the optimization to minimize the daily electricity cost. This paper analyzes the cost-saving effects by the each operating time-interval in case that the RFB ESS is optimally scheduled for peak shaving and load leveling.

• Journal of Microbiology and Biotechnology
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• v.31 no.1
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• pp.79-91
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• 2021

γ-Glutamylcysteine synthetase (Gcs1) and glutathione reductase (Glr1) activity maintains minimal levels of cellular methylglyoxal in Candida albicans. In glutathione-depleted Δgcs1, we previously saw that NAD(H)-linked methylglyoxal oxidoreductase (Mgd1) and alcohol dehydrogenase (Adh1) are the most active methylglyoxal scavengers. With methylglyoxal accumulation, disruptants lacking MGD1 or ADH1 exhibit a poor redox state. However, there is little convincing evidence for a reciprocal relationship between methylglyoxal scavenger genes-disrupted mutants and changes in glutathione-(in)dependent redox regulation. Herein, we attempt to demonstrate a functional role for methylglyoxal scavengers, modeled on a triple disruptant (Δmgd1/Δadh1/Δgcs1), to link between antioxidative enzyme activities and their metabolites in glutathione-depleted conditions. Despite seeing elevated methylglyoxal in all of the disruptants, the result saw a decrease in pyruvate content in Δmgd1/Δadh1/Δgcs1 which was not observed in double gene-disrupted strains such as Δmgd1/Δgcs1 and Δadh1/Δgcs1. Interestingly, Δmgd1/Δadh1/Δgcs1 exhibited a significantly decrease in H2O2 and superoxide which was also unobserved in Δmgd1/Δgcs1 and Δadh1/Δgcs1. The activities of the antioxidative enzymes erythroascorbate peroxidase and cytochrome c peroxidase were noticeably higher in Δmgd1/Δadh1/Δgcs1 than in the other disruptants. Meanwhile, Glr1 activity severely diminished in Δmgd1/Δadh1/Δgcs1. Monitoring complementary gene transcripts between double gene-disrupted Δmgd1/Δgcs1 and Δadh1/Δgcs1 supported the concept of an unbalanced redox state independent of the Glr1 activity for Δmgd1/Δadh1/Δgcs1. Our data demonstrate the reciprocal use of Eapx1 and Ccp1 in the absence of both methylglyoxal scavengers; that being pivotal for viability in non-filamentous budding yeast.

• Molecules and Cells
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• v.39 no.8
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• pp.631-638
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• 2016

Glutathione peroxidase 3 (GPx3), an antioxidant enzyme, acts as a modulator of redox signaling, has immunomodulatory function, and catalyzes the detoxification of reactive oxygen species (ROS). GPx3 has been identified as a tumor suppressor in many cancers. Although hyper-methylation of the GPx3 promoter has been shown to down-regulate its expression, other mechanisms by which GPx3 expression is regulated have not been reported. The aim of this study was to further elucidate the mechanisms of GPx3 regulation. GPx3 gene analysis predicted the presence of ten glucocorticoid response elements (GREs) on the GPx3 gene. This result prompted us to investigate whether GPx3 expression is regulated by the glucocorticoid receptor (GR), which is implicated in tumor response to chemotherapy. The corticosteroid dexamethasone (Dex) was used to examine the possible relationship between GR and GPx3 expression. Dex significantly induced GPx3 expression in H1299, H1650, and H1975 cell lines, which exhibit low levels of GPx3 expression under normal conditions. The results of EMSA and ChIP-PCR suggest that GR binds directly to GRE 6 and 7, both of which are located near the GPx3 promoter. Assessment of GPx3 transcription efficiency using a luciferase reporter system showed that blocking formation of the GR-GRE complexes reduced luciferase activity by 7-8-fold. Suppression of GR expression by siRNA transfection also induced down-regulation of GPx3. These data indicate that GPx3 expression can be regulated independently via epigenetic or GR-mediated mechanisms in lung cancer cells, and suggest that GPx3 could potentiate glucocorticoid (GC)-mediated anti-infla-mmatory signaling in lung cancer cells.

• Journal of Plant Biotechnology
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• v.43 no.3
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• pp.281-292
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• 2016

Plants can recognize and respond in various ways to diverse environmental stresses, including pathogenic microorganisms, salt, drought, and low temperature. Salicylic acid (SA) is one phytohormone that plays important roles in the regulation of plant growth and development. Nonexpressor of pathogenesis-related genes 1 (NPR1) was originally identified as a core protein that could function as a transcriptional co-regulator and SA receptor during systemic acquired resistance (SAR), a plant immune response that could activate PR genes after pre-exposure of a pathogen. Although the function of NPR1 in plant defense response and the role of SA hormone in the regulation of plant physiological processes have been well characterized, the biological role of NPR1 in plant abiotic stress responses is largely unknown. In this review, we will summarize and discuss the current understanding of NPR1 function in response to plant environmental stresses.