• Journal of the Korean Chemical Society
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• v.30 no.5
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• pp.409-414
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• 1986

The reduction of $VO_2^+$ ion by ethanol in sulfuric acid leads to the formation of vanadyl sulfate. Spectrophotometric measurements on the solution containing products, vanadyl sulfate, are also reported. Kinetic studies on reduction of $VO_2^+$ by ethanol have been carried out at 35${\circ}C$ and 50${\circ}C$. The reaction mechanism for reduction of $VO_2^+$ is discussed.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.4 no.2
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• pp.103-110
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• 2000

In order to understand the wintertime intermittent characteristics of the trans-boundary air pollutant transport observed in East Asia, a numerical simulation of the long-range transport of pollutants was applied using an atmospheric transport model(STEM-II). The numerical simulation was carried out for the entire month of January 1997 and specific atmospheric aerosol (including sulfate, nitrate, and other ion compounds0 observation data were compared from four observation sites(Cheju Island, Kanghwa Island, Dazaifu, and Fukue Island). The observation data revealed that concentration peaks were intermittently observed at 3 to 4-day intervals plus the four observation sites exhibited a very similar spatial variation. The horizontal and spatial scale of the heavily polluted air masses was analyzed based on numerical results. The mechanism of the intermittent transport of air pollutants was clearly explained by a comparison of the observed data with the numerical output. It was found that the wind pattern variations associated with the synoptic scale pressure system changes play an extremely important role in the transport of pollutants in this region.

• Textile Coloration and Finishing
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• v.6 no.2
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• pp.40-46
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• 1994

In order to study the properties of cochineal color, variation of uv, visible spectra by pH, dyeing properties on the silk in several dyeing conditions and thermodynamic parameter were investigated. Cochineal colors had an unusual to pH, especially had instability in alkali condition. An increase in the dyeing temperature and in time resulted in an increase in the dye content of silk fibers. Concentration of cochineal color in the silk fiber was related to pH and the maximum exhaustion of cochineal colors showed at about pH 3. The value of apparent diffusion coefficients and standard affinities of dyeing increased with the increase of dyeing temperature. The standard heats of dyeing(ΔH°), variation of entropy(ΔS°) and activation energy(E/sub act/) were caculated to be -1.72kcal/mo1, -3.77cal/mo1ㆍdeg and 1.26kcal/mo1, respectively. Silk fabrics were dyed bright red by tin chloride, reddish purple by copper sulfate, and bluish gray by iron sulfate, respectively. Lightfastness of silk fabrics mordanted by metal ion was weak.

• Korean Journal of Microbiology
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• v.25 no.2
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• pp.148-156
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• 1987

Extracellular laccase (E.C. 1.10.3.2) from the culture filtrate of Pleurotus ostreatus was purified by ammonium sulfate precipctation, protamine sulfate precipitation, DEAE-Sephadex A-50 ion exchange chromatography and Sephadex G-100 gel permeation chromatography. The molecular weight of the enzyme was estimated by SDS-polyacrylamide gel electrophoresis to be 58,000 and the isoelectric point was 3.75. The optimum temperature for the enzyme was about $45^{\circ}C$ and the optimum pH was 6.5. The enzyme was found to be stable at temperature below $35^{\circ}C$ and rapidly inactivated at higher temperatures. Km values for ferulic acid, vanillic acid, dihydroxyphenylalanine (DOPA) were 48.6.$\mu$M, 0.52mM, and 2.73mM, respectively, which indicates that the enzyme has much higher affinity towards ferulic acid. The reaction products of the enzyme were separated by TLC and HPLC.

• Corrosion Science and Technology
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• v.16 no.5
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• pp.227-234
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• 2017

Reference electrodes are generally implemented for the purpose of monitoring the cathodic protection potentials of buried or immersed metallic structures. In the market, many types of reference electrodes are available for this purpose, such as saturated calomel, silver/silver chloride and copper/copper sulfate. These electrodes contain a porous ceramic junction plate situated in the cylindrical body bottom to permit ionic flux between the internal electrolyte (of the reference electrode) and the external electrolyte. In this work, the copper/copper sulfate reference electrode was modified by replacing the porous ceramic junction plate for a metallic platinum wire. The main purpose of this modification was to avoid the ion copper transport from coming from the inner reference electrode solution into the surrounding electrolyte, and to mitigate the copper plating on the coupon surfaces. Lab tests were performed in order to compare the performance of the two mentioned reference electrodes. We verified that the experimental errors associated with the measurements conducted with developed reference electrode would be negligible, as the platinum surface area exposed to the surrounding electrolyte and/or to the reference electrolyte are maintained as small as possible.

• BMB Reports
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• v.36 no.2
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• pp.185-189
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• 2003

Chitinase (EC 3.2.1.14) was isolated from the culture filtrate of Streptomyces sp. M-20 and purified by ammonium sulfate precipitation, DEAE-cellulose ion-exchange chromatography, and Sephadex G-100 gel filtration. No exochitinase activity was found in the culture filtrate. The molecular mass of the purified chitinase was 20 kDa, estimated by a sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and was confirmed by activity staining with Calcofluor White M2R. Chitinase was optimally active at pH of 5.0 and at $30^{\circ}C$. The enzyme was stable from pH 4 to 8, and up to $40^{\circ}C$. Among the metals and inhibitors that were tested, the $Hg^+$, $Hg^{2+}$, and p-chloromercuribenzoic acid completely inhibited the enzyme activity. The chitinase activity was high on colloidal chitin, chitotriose, and chitooligosaccharide. The purified chitinase showed antifungal activity against Botrytis cinerea, and lysozyme activity against the cell wall of Botrytis cinerea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.6
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• pp.728-735
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• 1995

The peptidyl prolyl cis-trans isomerase(PPlase, EC 5.2.2.8) from Bacillus stearothermophilus SIC1 was extracted from the cells treated with by lysozyme. PPlase was purified from the cell extracts by heat treatment, ammonium sulfate precipitation, ion exchange chromatography and finally gel filtration (FPLC). The purity of purified the enzyme after Superose 12 column chromatography was examined by sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE). The molecular weight of the purified PPlase was estimated as 18,000 by SDS-PAGE. The 39 amino acid residues from the N-terminus were determined by the protein sequencer. The enzyme showed the optimum pH at 8.0 and was stable at the range of pH 7.0 to 8.0. The enzyme was considerably stable after heat treatment at $60^{\circ}C$ for 30 minutes, and the enzyme was quite stable up to $65^{\circ}C$. The presence of the PPlase in the refolding solution accelerated the isomerization rate of the assay peptide.

• The Korean Journal of Food And Nutrition
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• v.9 no.1
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• pp.85-91
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• 1996

B-amylase(EC 3.2.1.2) was isolated from the root of arrowroot(Peuria thunbergiana Bentham) with distilled water and then fractionated with ammonium sulfate. Crude extract was partially purified by ion exchange chromatography and gel filtration. The enzymatic properties of partially purified $\beta$-amylase were as follows, the enzyme was fractionated with ammonium sulfate between 0.2 and 0.4 saturation, and showed the typical reaction properties of B-amylase producing only maltose from starch. Optinum pH and temperature were pH 6.5, $50^{\circ}C$ respectively. The activity of the enzyme had proportional relations with enzyme protein concentration below 4mg, and had Michaelis constant of 66.7mg% for soluble starch. The enzyme was inhibited by some metal louts such as silver, cadmium, mercury, aluminum, iron and copper.

• Journal of Microbiology
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• v.34 no.1
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• pp.82-89
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• 1996

Purine nucleoside phosphorylase (PNP) was purified in Micrococcus luteus (M. luteus) using streptomycin sulfate and amomonium sulfate fractionation, three times by a Sephadex G-100 gel filtration and a DEAE-Sephadex A-50 ion exchange chromatography. The enzyme was purified 72 folds with a 11% recovery and showed a single band in a nondenaturing gel electrophoresis. The M. W. of PNP turned out to be 1.35 * 10$^{5}$ delton in G-150 gel filtration chromatography. The stability of the enzyme was increased by treatment with both substrates, MgCI$_{2}$ or CaCI$_{2}$, but not significantly kcal/mol. M. luteus PNP catalyzed the phosphorolysis of inosine, deoxyinosine, guanosine and deoxyguanosine with the Km value of 1.5 * 10$^{-3}$ M, 3.0 * 10$^{-3}$ M, 5.0 * 10$^{-4}$ M, respectively. The enzyme was reacted with adenosine, 1-methylnosine and 1-methylguanosine as substrates, which were shown to be poor substrates for mammalian enzyme.

• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.4
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• pp.388-394
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• 1991

Alkaline protease producing bacteria were isolated from soil and identified as Bacillus sp. CW-1121. It was found that the production of alkaline protease reached to maximum in 5 day of fermentation at 4$0^{\circ}C$. The enzyme was purified by ammonium sulfate precipitation, gel filtration on Sephadex G-150 and DEAE-cellulose ion-exchange chromatography. The homogeneity of the purified enzyme was verified by polyacrylamide gel electrophoresis. The enzyme was purified 5.72 fold and yield of the enzyme purification was 16.71%. When the purified enzyme was applied to sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the molecular weight was estimated to be 55, 000.