• Journal of the Korean Chemical Society
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• v.29 no.3
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• pp.295-303
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• 1985

Carboxypeptidase B from Salmo Salar eggs was purified by CM-cellulose, 0.5 ammonium sulfate saturation, DEAE-cellulose, and Sephadex G-75 gel filtration and its enzymatic properties were investigated. Optimum temperature was 55$^{\circ}C$, pH optima were 4.0 and 7.0 at 37$^{\circ}C$, and the enzyme was stable at pH 2.0∼3.0 and 5.5∼7.0 for 1.5h. This enzyme showed substrate specificity hydrolyzing the peptide bond of glycyl-L-arginine. Its K$_m$ values was 0.21mM, and the enzyme activity was stimulated by Cu$^{2+}$ and Fe$^{3+}$, while inhibited by Zn$^{2+}$. The lysine was found to be competitive inhibitor and its K$_i$ value was determined to be 4.3mM. Molecular weight of this enzyme was determined to be 36,400 daltons by SDS-PAGE and the enzyme was monomeric protein composed of 19 kinds of amino acid residues.

• Microbiology and Biotechnology Letters
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• v.17 no.4
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• pp.397-402
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• 1989

A new extracellular biopolymer was produced by Methylobacterium organophilum from methanol as a sole carbon and energy source. The purified biopolymer was found to have a high molecular weight of about 4-5$\times$10$^6$ dalton and contained 66% (w/w) of carbohydrate but no polyhydro xybutyrate. Other organic constituents were consisted of protein, pyruvic acid, uronic acid, and acetic acid, whereas content of inorganic ash was 22%. Based on the chemical analysis of the biopolymer by TLC method, the polymer was consisted of glucose, galactose, and mannose with an approximate molar ratio of 2:3:2. The biopolymer solution showed a characteristics of pseudoplastic non-Newtonian fluid. The viscosity of the 1%-biopolymer solution was found to be 18,000 cp at a shear rate, 1 sec$^{-1}$, which was almost 10 times higher than that of a commercial xanthan gum.

• KSBB Journal
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• v.14 no.6
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• pp.724-730
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• 1999

Characteristics and enzyme activity comparison was made between urokinase isolated from urine and pro-urokinase separated from CHO(Chinese Hamster Ovary) cell culture broth. Both of purified urokinase and pro-urokinase resulted 54Kd single band in electrophoresis. Urokinase which was proved as a single molecule by gel filtration showed two separated 33Kd and 21Kd bands by 2-mercaptoethanol reduction. Isoelectric forcusing resulted same pl value of 8.6 for both of them. N-terminal amino acid sequence of urokinase after 159th Ile was Ile-Gly-Gly-Glu-Phe-Thr-Thr-Ile-Glu which was different from another N-terminal sequence of Ser-Asn-Glu-Leu-His-Gln-Val-Pro-Ser-Asn. Thrombolytic activities of both of them were propotional to the enzyme concentration. Urokinase showed thrombolytic activities in an short period of reaction time. Pro-urokinase, however, showed high thrombolytic activity for 2 hours or longer period of reaction time.

• The Korean Journal of Mycology
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• v.24 no.3 s.78
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• pp.237-242
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• 1996

Two depsides, medicinal herb products isolated from the methanol extract of Umbilicaria esculenta, inhibited human synovial fluid Phospholipase $A_2\;(PLA_2)$ ($IC_{50}$ of 0.22 and 0.26 mM, respectively). In the course of screening for antiinflammatory compounds from natural products, we successfully isolated two depsides $PLA_2$ inhibitory compounds, Orcinol and methyl orsellinic acid. The compounds were identified as orcinol and methyl orsellinic acid on the basis of various NMR studies including $^1H,\;^{13}C$ and DEPT experiments.

• Korean Journal of Optics and Photonics
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• v.29 no.6
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• pp.275-284
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• 2018

In this study we propose a hybrid color-filter design method in which a nanohole array and a nanodisk array are separated by nanopillars of the material AZ 1500. We propose a design method for an RGB color filter, using the tendency of transmitted light according to each design variable. Especially we analyzed the intensity distribution of the electric field in the cross section, and set the height of the nanopillars so that the local surface-plasmon resonances generated in the two different arrays do not affect each other. The optical characteristics of the optimized color filter are as follows: In the case of the red filter, the ratio of the wavelength band expressing red in the visible broadband is 55.01%, and the maximum transmittance is 41.53%. In the case of the green filter, the ratio of the wavelength band expressing green is 40.20%, and the maximum transmittance is 42.41%. In the case of the blue filter, the ratio of the wavelength band expressing blue is 32.78%, and the maximum transmittance is 30.27%. We expect to improve the characteristics of color filters integrated in industrial devices by this study.

• Applied Biological Chemistry
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• v.36 no.3
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• pp.158-162
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• 1993

A bilirubin oxidase produced by Penicillium sp. strain LAM 91-89 was purified and partially characterized. The enzyme was purified about 70 folds from culture broth by ethanol precipitation, first and second Sephadex G-200 column chromatography with overall yield of 12%. The molecular weight of the enzyme was estimated to be 53,000 dalton by SDS-PAGE. The optimum pH and temperature was 8.5 and $40^{\circ}C$, respectively. The enzyme was stable in the pH range $6{\sim}10$ and below $40^{\circ}C$. Activity of the enzyme was increased by the addition of $Mg^{2+}$ but was gretly inhibited by $Ag^+,\;Hg^{2+},\;Mn^{2+},\;Pb^{2+}$, iodoacetate, p-chloromercurobenzoic acid and sodium dodecyl sulfate. Among various substrates, bilirubin was favorably reacted and $K_m$ value for bilirubin was $6.67\;{\mu}mole$.

• Journal of the Korean Chemical Society
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• v.23 no.3
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• pp.165-174
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• 1979

A purification technique of glucose oxidase was developed. Using the gluconyl-${\omega}$-aminohexyl Sepharose affinity chromatography, it was partially purified 14.6 folds with 79.7% yield. With the combination of the affinity chromatography and Sepharose 6B gel filtration, the enzyme was purified 27.2 folds from the broth with 74.1% yield. The final purified preparation showed 90.83 U of glucose oxidase activity per mg of protein and a single band by 7% polyacrylamide gel electrophoresis. The absorption spectrum and substrate specificity of the enzyme were studied and the fianal preparation showed the optimal pH between 5.6 and 6.0, the optimal temperature at $40^{\circ}C$, $8.5{\times}10^{-3}M$ of $K_m$ for D-glucose, and 3.43 kcal/mole of the activation energy.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.3
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• pp.39-49
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• 2003

The delta operator approach and the singular perturbation technique are introduced. The former reduces the round-off error in the numerical computation. The latter reduces computing time by decoupling the original system into the fast and slow sub-systems. The aircraft dynamics consists of the Phugoid and short-period motions whether its model is longitudinal or lateral. In this paper, an approximated solutions of lateral dynamic model of Beaver obtained by using those two methods in compared with the exact solution. For open-loop system and closed-loop system, and approximated solution gets identical to the exact solution with only one iteration and without iteration, respectively. Therefore, it is shown that implementing those approaches is very effective in the flight dynamic and control.

• Applied Biological Chemistry
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• v.34 no.1
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• pp.49-53
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• 1991

Three polyphenol oxidase(polyphenol oxidase I, II and III ) were isolated from the crude extract of a Spuriopimpinella bracycarpa by $(NH_4)_2SO_4$ precipitation and subsequent Sephadex G-150 chromatography. The final preparation thus obtained showed three peaks of enzyme activity. Optimum pH and temperature for the activity of polyphenol oxidase were 7.5 and $30^{\circ}C$, respectively. The enzyme was completely inactivated when i4 was treated at$70^{\circ}C$ for 30min and at $80^{\circ}C$ for 5min at pH 6.5. The enzyme was partially inactivated by ascorbic acid, glutathione and potassium cyanide (0.1mM), and was completely inhibited by L-cysteine, ascorbic acid, glutathione and potassium cyanide(0.5 and 1.0mM). The enzyme has good activity on catechol and 3,4-dihydroxytoluene but was strongly inactivated on pyrogallol, dopamine and DL-dopa. The Michaelis cons4ant of the enzyme was 86.5mM with catechol as a substrate.

• Korean Journal of Food Science and Technology
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• v.35 no.3
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• pp.353-358
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• 2003

Volatile compounds of porcine liver were collected by simultaneous steam distillation and extraction and steam distillation under reduced pressure. Volatiles were analyzed by gas chromatography (GC) and GC-mass spectrometry. Key aroma compounds of off-flavor in porcine liver were characterized using GC-olfactometry technique. Concentrates of cooked porcine liver had odor of a typical liver, fishy, and metallic off-flavor. Aroma concentrates showed over 90 peaks, of which 69 compounds were positively and/or tentatively identified. 1-Octen-3-one, 1-hexanol, (E)-2-nonenal, (Z)-4-decenal, (E,E)-2,4-heptadienal and (E,E)-2,4-decadienal were newly identified in this study. These compounds seem to be produced from unsaturated fatty acids of porcine liver by oxidation. 1-Octen-3-one (metallic), 1-hexanol (metallic) and (E,E)-2,4-heptadienal(fishy) have been implicated in fishy and metallic off-flavor in cooked porcine liver.