• Korean Journal of Microbiology
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• v.32 no.4
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• pp.315-321
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• 1994

Glyoxalase I was purified 2,294-fold from Pleurotus ostreatus by S-hexylglutathione affinity chromatography, Sephadex G-150 gel filtration chromatography and DEAE-sepharose A-50 CL-6B ion exchange chromatography with an overall yield of 21.7%. The molecular mass determined by gel filtration was found to be approx. 34 kDa. SDS-PAGE revealed that the enzyme consists of two identical subunits with a molecular mass of approx. 17 kDa. The K sub(m) values of this enzyme for methylglyoxal and phenylglyoxal were 0.39 mM and 0.22 mM, respectively. And this enzyme had a strong affinity for L-xylosone and hydroxypyruvaldehyde. The enzyme showed its optimal activity at pH 6.5-7.5 and at $40^{\circ}C$. $^1H$-NMR spectroscopic analysis of enzymic reaction showed that this enzyme catalyzes intramolecular proton transfer.

• Membrane Journal
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• v.32 no.5
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• pp.283-291
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• 2022

Hydrogen energy has received much attention as a solution to the supply of renewable energy and to respond to climate change. Hydrogen is the most suitable candidate of storing unused electric power in a large-capacity long cycle. Among the technologies for producing hydrogen, water electrolysis is known as an eco-friendly hydrogen production technology that produces hydrogen without carbon dioxide generation by water splitting reaction. Membranes in water electrolysis system physically separate the anode and the cathode, but also prevent mixing of generated hydrogen and oxygen gases and facilitate ion transfer to complete circuit. In particular, the key to next-generation anion exchange membrane that can compensate for the shortcomings of conventional water electrolysis technologies is to develop high performance anion exchange membrane. Many studies are conducted to have high ion conductivity and excellent durability in an alkaline environment simultaneously, and various materials are being searched. In this review, we will discuss the research trends and points to move forward by looking at the research on anion exchange membranes based on commercial polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS) block copolymers.

• Journal of Life Science
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• v.24 no.2
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• pp.186-190
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• 2014

Carbonic anhydrase isozymes (CAs) are widespread zinc-containing metalloenzyme family. The enzyme catalyzes the reversible interconversion of $CO_2$ and $HCO_3$. This reaction is the main role of CA enzymes in physiological conditions. CA III, one of the CA isozymes, has been identified in many tissues. It is distinguished from the other isozymes by several characteristics, particularly by a lower specific activity and by its resistance to acetazolamide. However, the physiological function of CA III in fish is unknown. In this study, we examined the detection of CAs in the Shaggy sea raven Hemitripterus villosus, using SDS-PAGE, isoelectric focusing (IEF), and western blot analysis. We detected a significant protein band with molecular weight about 30 kDa from the tissues of H. villosus by SDS-PAGE and western blotting. A specific band of CA III with pI 7.0 was detected by IEF and western blotting in gill and muscle. The immunoreaction of anti-CA III expressed in the gill of H. villosus was much stronger than other tissues. One explanation for this result is that the fish gill is the only organ that is exposed to the external environment and that plays an important role in acid-base relevant ion transfer, the transfer of $H^+$ and/or $HCO{_3}^-$, for the maintenance of systemic pH. This is the first report on the identification of a carbonic anhydrase III-like protein from H. villosus.

• Journal of Life Science
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• v.23 no.12
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• pp.1557-1561
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• 2013

Carbonic anhydrase isozymes are a widespread, zinc-containing metalloenzyme family. The enzyme catalyzes the reversible inter-conversion of $CO_2$ and $HCO_3$. This reaction is the main role played by CA enzymes in physiological conditions. This enzyme has been found in virtually all organisms, and at least 16 isozymes have been isolated in mammals. Unlike mammals, there is little information available regarding CA isozymes in the tissues of non-mammalian groups, such as fish. Carbonic anhydrase is very important in the osmotic and acid-base regulation in fish. It is well-known that the gills of fish play the most important role in acid-base relevant ion transfer, the transfer of $H^+$ and/or $HCO_3^-$, for the maintenance of systemic pH. Rainbow trout, Oncorhynchus mykiss, is the most important freshwater fish species in the aquaculture industry of Korea, with annual production increasing each year. In addition, environmental toxicology research has shown that rainbow trout is known to be the species that is most susceptible to environmental toxins. Consequently, carbonic anhydrase was detected in rainbow trout, Oncorhynchus mykiss. The isolated protein showed the specific band with a molecular weight of 30 kDa and pI of 7.0, and it was identified as being carbonic anhydrase. The immunohistochemical result demonstrated that the carbonic anhydrase was located in the epithelial cells of the gills.

• Membrane Journal
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• v.18 no.4
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• pp.261-267
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• 2008

A graft copolymer consisting of poly(vinyl chloride) (PVC) backbone and poly(hydroxyethyl acrylate) (PHEA) side chains was synthesized via atom transfer radical polymerization (ATRP). Direct initiation of the secondary chlorines of PVC facilitates grafting of hydrophilic PHEA monomer. This graft copolymer, i.e. PVC-g-PHEA was cross-linked with sulfosuccinic acid (SA) via the esterification reaction between -OH of the graft copolymer and -COOH of SA, as confirmed by FT-IR spectroscopy. Ion exchange capacity (IEC) continuously increased to 0.87meq/g with increasing concentrations of SA, due to the increasing portion of charged groups in the membrane. However, the water uptake increased up to 20.0wt% of SA concentration above which it decreased monotonically. The membrane also exhibited a maximum proton conductivity of 0.025 S/cm at 20.0 wt% of SA concentration, which is presumably due to competitive effect between the increase of ionic sites and the crosslinking reaction.

• Biomedical Science Letters
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• v.6 no.4
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• pp.237-244
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• 2000

It has been reported that plasma membrane activity of the spermatozoa may be susceptible to be influenced by extracellular osmolality and such membranous changes involve infracellular molecular changes, special regard to the structure of membranous lipids, and the accompanying ion-channel of which are closely related with their fluidity of $Ca^{2+}$ and HCO$^{-}_{3}$. It is of common recognition that a certain kind of sterol acceptor player an important to induce lipid fluctuation of the sperm plasma membrane which have been influenced by BSA administration and came in effect to outflow of cholesterol from the spermatozoa and resulted in changes of ionic fluidity to facilitate adenylyl cyclase, and to induce protein tyrosine phosphorylation by increase of cAMP and activation of PKA. Thus it seems likely that an augmentation of the acrosomal reaction is closely related with protein tyrosine phosphorylation. The following experimental results were obtained in the present study; Under the high osmolality conditions, the spermatozoa motility declined significantly and the structural change of the plasma membrane diminished to confirm that the response degrees to the osmolality depended upon the water transfer volume through the plasma membrane and the changes of cellular volume. Those experimental results suggest that a physiological parameter such as low temperature condition played an important role for presentation of spermatozoa and that inducement of spermatozoa activation for reinforcement of protein tyrosine phosphorylation. On the other hand, it seemed likely that the BSA administration as one of sterol accepters might represent a key role also under the high osmolality condition and their result also suggests that osmolality change, special regard to high osmolality condition may play an important role also in the processes of signal transmission.

• Journal of the Korean Chemical Society
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• v.55 no.2
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• pp.177-182
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• 2011

A diketo-type ligand was synthesized by the Knoevenagel condensation reaction of thiophene-2-aldehyde with acetylacetone, subsequently its transition metal complexes with Cu(II), Ni(II), and Co(II) chlorides were also prepared. All the complexes were characterized by various physico-chemical methods. The molar conductivity data reveals ionic nature for the complexes. The electronic spectrum and the EPR values suggest square planar geometry for the Cu(II) ion. Interaction of the Cu(II) complex with CTDNA (calf thymus DNA) was studied by absorption spectral method and cyclic voltammetry. The $k_{obs}$ values versus [DNA] gave a linear plot suggesting psuedo-first order reaction kinetics. The cyclic voltammogram of the Cu(II) complex reveals a quasi-reversible wave attributed to Cu(II)/Cu(I) redox couple for one electron transfer with $E_{1/2}$ values -0.240 V and -0.194 V. respectively. On addition of CTDNA, there is a shift in the $E_{1/2}$ values 168 mV and 18 mV respectively and decrease in Ep values. The shift in $E_{1/2}$ values in the presence of CTDNA suggests strong binding of Cu(II) complex to the CTDNA.

• Journal of the Korean Electrochemical Society
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• v.7 no.1
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• pp.21-25
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• 2004

The electrochemical behaviors of dissolved hydrogen and hydrogen peroxide at a platinum disk electrode were investigated in boric acid solution by potentiostatic polarization method at the temperature of 25 and $200^{\circ}C$. The oxidation of dissolved hydrogen at $25^{\circ}C$ was kinetically controlled reaction, the rate of which depends upon the electron transfer on the electrode surface. As temperature was raised, however, the electrochemical characteristics of dissolved hydrogen were changed from a kinetically controlled reaction to a diffusion controlled one. One notable feature, with dissolved hydrogen at high temperature, is that an abnormal potential range was observed, where the oxidation rate of dissolved hydrogen rapidly decreased just before starting potential of water oxidation. We think it is caused by the deactivation of the electrode that results from the adsorption of hydroxyl ion on the surface of the platinum disk. On the contrary, a definite change with temperature was not identified in the case of the hydrogen peroxide except for the increase in current density that was due to the increasing diffusion coefcient with an increase of temperature.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.4
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• pp.733-742
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• 2000

Fundamental materialistic characterization and adsorption/neutralization behavior of waste egg shell for heavy metal ion have been studied for its application to wastewater treatment. To investigate the structural change and thermal decomposition characteristics of egg shell. X-ray diffraction and FT-IR analysis were conducted for egg shell treated at $105^{\circ}C$ and $700^{\circ}C$, respectively. For the result of FT-IR analysis, the sample treated at $700^{\circ}C$ showed a reduced C-O absorption band compared with that of egg shell treated at $105^{\circ}C$, which may be due to the $CO_2$ release. Unlike to the result of FT-IR analysis, the XRD patterns of egg shell were almost similar for the cases of $105^{\circ}C$ and $700^{\circ}C$ treatment. however, characteristic diffraction pattern of CaO was observed for $850^{\circ}C$ treatment, at which $CaCO_3$ is known to be completely converted to CaO. TGA/DTA analysis showed a slow decline in weight loss up to $600^{\circ}C$ and, for $600{\sim}800^{\circ}C$ range, the weight loss became drastic by reason of $CO_2$ discharge, which was accompanied by an appearance of major endothermic peak. The ratio of practical breakthrough time to ideal one, total transfer unit, and mass transfer coefficient were observed to be increased as the adsorption was progressed in a multiple-column fixed-bed reactor using egg shell as an adsorbent, which signified the distribution effect of mass transfer for continuous adsorption reaction. The neutralization effect of egg shell for several types of acidic wastewater made of different mineral acids was not much different from each other except for the case of $H_2SO_4$, for which the neutralization reaction was thought to be retarded by the formation of gypsum.

• Applied Chemistry for Engineering
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• v.27 no.6
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• pp.653-658
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• 2016

In this work, we developed a synthetic method for preparing one-dimensional $MnO_2$ nanowires through a hydrothermal method using a mixture of $KMnO_4$ and $MnSO_4$ precursors. As-prepared $MnO_2$ nanowires had a high surface area and porous structure, which are beneficial to the fast electron and ion transfer during electrochemical reaction. The microstructure and chemical structure of $MnO_2$ nanowires were characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and Brunauer-Emmett-Teller measurements. The electrochemical properties of $MnO_2$ nanowire electrodes were also investigated using cyclic voltammetry and galvanostatic charge-discharge with a three-electrode system. $MnO_2$ nanowire electrodes showed a high specific capacitance of 129 F/g, a high rate capability of 61% retention, and an excellent cycle life of 100% during 1000 cycles.