• Bulletin of the Korean Chemical Society
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• v.25 no.9
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• pp.1366-1370
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• 2004

Controlled pore glass bead was modified with bovine serum albumin (BSA), and glutathione (GSH) was immobilized through three kinds of linkers on top of BSA. Bis(3-sulfo-N-hydroxysuccinimide suberate) sodium salt $(BS^3)$, N-hydroxysuccinimide 3-(2-pyridyldithio)propionate (SPDP), or N-hydroxysuccinimide 4-maleimidobutyrate (GMBS) was introduced into the BSA-bound matrix. Subsequently, GSH was immobilized by addition of thiol side chain into the maleimido moiety, replacing a disulfide group, or formation of an amide group upon releasing 3-sulfo-N-hydroxysuccimide group. It was observed that conjugation methodology played a critical role for activity of the immobilized GSH. SDS-PAGE chromatogram showed that the matrix of glutathione immobilized on BSA through GMBS manifested high selectivity towards glutathione-S-transferase (GST) in cell lysate.

• YAKHAK HOEJI
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• v.47 no.6
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• pp.450-455
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• 2003

Synthesis of (lR,5S,6S)-6-[(lR)-1-hydroxyethyl] -2-[(3S,5S)-5-(2-ethoxycarbonyl-1-moxy(hydroxy)iminoethyl)pyrrolidine-3-ylthio]-1-methylcarbapen-2-em-3-carboxylic acids (10a,l0b) were described. Methyl(2S,4S)-4-tritylthio-1-(allyloxycarbonyl)pyrrolidine-2-carboxyla late (I) was prepared from trans-4-hydroxy-L-proline with (2S,4R)-abs olute configuration as starting material. (2S,4S)-1-allyloxycarbonyl-2-(2-ethoxycarbonyl-hydroxy(methoxy )iminoethyl)-4-mercapto- pyrrolidines (6,7) were obtained from the tritylthio compound (I). (lR,5S,6S)-6-[(lR)-1-hydroxyethyl]-2-[(3S,5S)-5-(2-ethoxycarbonyl-1-methoxy(hydroxy)imino-ethyl)pyrrolidine-3-ylthio]-1-methylcarbapem-2-em-3-carboxylic acids (10a,10b) were obtained by the coupling reaction with carbapenem diphenylphosphates (8) and pyrrolidine-thiol moiety (6,7). Their in vitro antibacterial activities against both Gram-positive and Gram-negative were tested. Compounds ( 10a,10b) showed potent antibacterial activity except pseudomonas aerusinosa.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.3
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• pp.111-114
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• 2005

Organic monolayers were fabricated onto Au(l l l) substrate by self-assembly method using dipyridinium. Also, organic single molecule in the organic monolayers was selected to measure the current-voltage (I-V) curves by using the ultrahigh vacuum scanning tunneling microscopy (UHV-STM). The organic molecule used in the experiment was dipyridinium dithioacetate, which contains thiol functional group and can be self-assembled easily onto Au(l l l) substrate. The concentration of dipyridinium dithioacetate for self-assembly procedure was I [mM/L]. To confirm the formation of self-assembled mono layers (SAMs), the differences of thickness of the self-assembled organic monolayers were observed by using an ellipsometer, and the morphology and I-V curves of the SAMs were investigated by using UHV-STM. The applied voltages were from -2 [V] to +2 [V], temperature was 300 [K]. The vacuum for measuring current of the organic single molecule was 6 $\times$ 10$^{-8}$ [Torr]. As a result, properties of the negative differential resistance (NDR) in constant voltage were found.

• Journal of Electrical Engineering and Technology
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• v.4 no.1
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• pp.106-110
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• 2009

An amperometric glucose biosensor has been developed using viologen derivatives as a charge transfer mediator between a glucose oxidase (GOD) and a gold electrode. A highly stable self-assembled monolayer (SAM) of thiol-based viologen was immobilized onto the gold electrode of a quartz crystal microbalance (QCM) and GOD was immobilized onto the viologen modified electrode. This biosensor response to glucose was evaluated amperometrically in the potential of -300mV. Upon immobilization of the glucose oxidase onto the viologen modified electrode, the biosensor showed rapid response towards glucose. Experimental conditions influencing the biosensor performance, such as pH potential, were optimized and assessed. This biosensor offered excellent electrochemical responses for glucose concentration below ${\mu}$ mol level with high sensitivity and selectivity and short response time. The levels of the RSDs (<5%) for the entire analyses reflected the highly reproducible sensor performance. A linear calibration range between the current and the glucose concentration was obtained up to $4.5{\times}10^{-4}M$. The detection limit was determined to be $3.0{\times}10^{-6}M$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.23-27
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• 2003

Molecular self-assembled of surfactant viologen are of recent interest because they can from functional electrodes as well as micellar assemblies, which can be profitably utilized for display devices, photoelectrochemical studies and electrocatalysis as electron acceptor or electron mediator. Fromherz et al studied the self-assembly of thiol and disulfide derivatives of viologens bearing long n-alkyl chains on Au electrode surface. The electrochemical behavior of self-assembled viologen monolayer has been investigated with QCM, which has been known as nano-gram order mass detector. The self-assembly process of viologen was monitored using resonant frequency$({\Delta}F)$ and resonant resistance(R). The redox process of viologen was observed with resonant frequency $({\Delta}F)$.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1305-1306
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• 2006

A monolayer assembly of anthracene-viologen linked thiol ($AMVC_{8}SH$) was fabricated on a gold electrode by self-assembly method. Structural property of the self-assembled monolayers (SAMs) was carried out by optical and electrochemical method. Firstly, we investigated PL spectrum and UV/visible absorption for the optical properties in solution state. Secondly, we determined the characteristics of charge transfer in different electrolyte solutions by electrochemical quartz crystal microbalance (EQCM). From the data, the PL spectrum and UV/visible absorption were observed and the well-defined shape peaks were nearly equal charges during redox reactions and existed to an excellent linear relationship between the scan rates and existed to currents. The mass change was determined during redox reaction. The mass change behavior of SAMs was not only governed by the mobility of the ion in the viologen but the valence of the ion in the electrolyte solution.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1520-1522
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• 2003

Molecular self-assembled of surfactant viologen are of recent interest because they can from functional electrodes as well as micellar assemblies, which can be Profitably utilized for display devices, photoelectrochemical studies and electrocatalysis as electron acceptor or electron mediator. Fromherz et al studied the self-assembly of thiol and disulfide derivatives of viologens bearing long n-alkyl chains on Au electrode surface. The electrochemical behavior of self-assembled viologen monolayer has been investigated with QCM, which has been known as nano-gram order mass detector. The self-assembly process of viologen was monitored using resonant frequency (${\Delta}$F) and resonant resistance (R). The redox process of viologen was observed with resonant frequency (${\Delta}$F).

• Applied Biological Chemistry
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• v.40 no.5
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• pp.451-454
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• 1997

An attempt was made in this study to analyze volatile flavor components of fresh and odorless garlic (Allium sativum L.), Essential oils in fresh garlic and odorless garlic were isolated by a simultaneous steam distillation and extraction(SDE) method using n-pentane/diethy ether as solvent. A total of 21 and 22 components were identified by GC/MS from the essential oils of fresh garlic and odorless garlic, respectively. Diallyl trisulfide, diallyl disulfide and methyl allyl disulfide were found to be major volatile flavor components in fresh garlic and odorless garlic. By the preparation of ordorless garlic, 77.5% of diallyl trisulfide, 15.0% of diallyl disulfde, 72% of methyl allyl disulfide, and 78.4% of allyl thiol components in fresh garlic were lost. Eleven compounds including 2-vinyl-4H-1,3-dithiin, eugenol and 2-methoxy-4-vinyl-phenol were identified in odorless garlic, but not m fresh garlic.

• Proceedings of the KIEE Conference
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• 2007.11a
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• pp.86-87
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• 2007

An amperometric glucose biosensor has been developed using viologen derivatives as electron mediator of glucose oxidase (GOD) at Au electrode. Highly stable self assembled monolayer (SAM) of thiol-based viologen is immobilized onto the Au electrode followed byGOD is immobilized onto the viologen modified electrode. This biosensor response to glucose was evaluated amperometrically in the potential of -300 mV. Upon immobilization of glucose oxidase onto the viologen modified-electrode, the biosensor showed rapid response towards glucose. Experimental conditions influencing the biosensor performance such as, pH, potential were optimized and assessed. This biosensor offered an excellent electrochemical response for glucose concentration below ${\mu}mol$ level with high sensitivity and selectivity and short response time. The levels of the RSD's (< 5 %) for the entire analyses reflected the highly reproducible sensor performance. Using the optimized a linear relationship between current and glucose concentration was obtained up to $4.5{\times}10^{-4}$ M. In addition, this biosensor showed well reproducibility and stability.

• Molecules and Cells
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• v.39 no.1
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• pp.31-39
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• 2016

The peroxiredoxins (Prxs) constitute a very large and highly conserved family of thiol-based peroxidases that has been discovered only very recently. We consider here these enzymes through the angle of their discovery, and of some features of their molecular and physiological functions, focusing on complex phenotypes of the gene mutations of the 2-Cys Prxs subtype in yeast. As scavengers of the low levels of $H_2O_2$ and as $H_2O_2$ receptors and transducers, 2-Cys Prxs have been highly instrumental to understand the biological impact of $H_2O_2$, and in particular its signaling function. 2-Cys Prxs can also become potent chaperone holdases, and unveiling the in vivo relevance of this function, which is still not established, should further increase our knowledge of the biological impact and toxicity of $H_2O_2$. The diverse molecular functions of 2-Cys Prx explain the often-hard task of relating them to peroxiredoxin genes phenotypes, which underscores the pleiotropic physiological role of these enzymes and complex biologic impact of $H_2O_2$.