• Korean Journal of Pharmacognosy
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• v.22 no.2
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• pp.101-111
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• 1991

Polyphenol oxidase(PPO) was purified from an extract of Puerariae Radix by ammonium sulfate fractionation followed by Sephadex G-150 column chromatography, which resulted in a 56-fold increase in specific activity. The enzyme was optimum of pH 6.5. The optimum temperature of enzymic reaction was about $40^{\circ}$. The enzyme was thermostable with a half-life equal to 32 min at $70^{\circ}$. Km values of the PPO for catechol and pyrogallol from Lineweaver Burk plots were $1.3{\times}10^{-2}M$, $1.16{\times}10^{-2}M$, respectively. The substrate specificity of the Puerariae Radix PPO showed high affinity toward pyrogallol. Reducing reagents such as cysteine, potassium metabisulfite, ascorbic acid, 2-mercaptoethanol completely inhibited the PPO activity at $10^{-2}M$ level. Linewear-Burk analysis of inhibition data revealed that the inhibition by cysteine, 2-mercaptoethanol, 4-nitrocatechol, potassium cyanide was competitive with Ki values of $4.3{\times10^{-2}M,\;0.73{\times}10^{-6}M,\;6.9{\times}10^{-6}M,\;6.4{\times}10^{-7}M$, respectively. The browning reaction by PPO was observed to decrease temporarily with the addition of sodium diethyl dithiocarbamate, a well known copper chelating agent. Among the divalent cations, $Cu^{2+}$ ion was strong activator on PPO and $Mn^{2+},\;Co^{2+}$ ions was effect on PPO activity. $Zn^{2+},\;Mg^{2+}$ ions was inhibitor on PPO.

• Journal of Soil and Groundwater Environment
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• v.21 no.3
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• pp.6-13
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• 2016

The effect of blast oxygen furnace (BOF) slag used as filling materials on the soil environment was studied using column tests that simulated the flow of the BOF slag leachate through the soil layer. The Cu, Mn, Zn, Ni, and F contents of the leachate affected soil were similar to that of the controls (i.e., soils that were not affected by the leachate). The As, Cd, and Pb contents were lower in the leachate affected soils than the controls. The changes in these contaminants contents can be attributed to the interactions between anions such as alkalinity generating anions (e.g., CO₃²⁻, HCO₃⁻, OH⁻) or calcium ions with heavy metals or F, which consequently affected the fate of heavy metals and F in the leachate affected soils. The germination and growth of Spinapis alba in the soils affected by the leachate and the controls were also similar. However, the proportion of alkalophilic bacteria in the soils affected by the leachate significantly increased, and this can be explained by the increased soil pH due to the alkaline leachate. Overall, this study shows that the alkalinity of the BOF slag leachate, rather than the presence of heavy metals and F in the leachate, needs to be considered when the BOF slag is to be reused as structural filling materials.

• Journal of Microbiology and Biotechnology
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• v.14 no.1
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• pp.97-104
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• 2004

Water-sludge bacteria were screened to find a lipase enantioselectively hydrolyzing itraconazole precursor, which is well known as the starting material of antifungal drug agents. A bacterial strain was isolated and identified as Acinetobacter junii SY-01. After the strain was cultivated, the enzyme was purified 39.4-fold using ultrafiltration and gel filtration through a Sephadex G-100 chromatographic column and the activity yield was 34.9%. The molecular weight of the enzyme was about 40 kDa, as measured by SDS-PAGE, and the optimum pH was 7.0- 9.0 and stable at pH 6.0- 9.0. The optimum temperature was 45- $5^{\circ}C$, and 73% of the enzymes activity remained after incubation at 70% for 1 h. Enzyme activity was enhanced by gall powder, sodium deoxycholate, a cationic detergent Tween 80, and a non-ionic detergent Triton X-100, but was markedly inhibited by metal ions such as $Hg^{2＋},Cu^{2＋},Ni^{2＋}/,Ca^{2＋}$, and an anionic-surfactant sodium dodecylsulfate. The $K_{m}$ values for (R)- and (S)-enantiomers of the itraconazole precursor were 0.385 and 21.83 mM, respectively, and the $V_{max} values ($\mu$Mㆍmin^{-1}.)$ were 6.73 and 6.49, respectively. The acetyl group among the different acyl moieties of itraconazole precursor showed the highest enantioselectivity for the hydrolysis by the Acinetobacter junii SY-01 lipase, and the lipase from Acinetobacter junii SY-01 displayed better enantioselectivity than that of commercially available lipases and esterases.

• Korean Journal of Pharmacognosy
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• v.30 no.3
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• pp.306-313
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• 1999

Polyphenol Oxidase(PPO) was purified from an extract of Ginkgo biloba leaves by ammonium sulfate fractionation followed by sephadex G-150 column chromatography, which resulted in a 18-fold increase in specific activity. The enzyme was most active at pH 8.5 and the temperature optimum for the PPO catechol oxidation reaction was $45^{\circ}C$. Heat inactivation studies showed that heating for 7, 9 and 48 min, at 80, 70 and $60^{\circ}C$ respectively caused a 50% loss in enzymatic activity and that the enzyme was completely inactivated after heat treatment at $90^{\circ}C$ for 60 min. Km values of the PPO for catechol, hydroquinone and 4-methylcatechol derived from Lineweaver-Burk plots were $6.06\;{\times}\;10^{-4}M,\;1.02\;{\times}\;10^{-3}M,\;1.41\;{\times}\;10^{-3}M$ respectively. Of the substrates tested, 4-methylcatechol was oxidized most readily and the enzyme did not oxidize monophenols. The enzyme datalyzed browning reaction was completely inhibited in the presence of reducing reagents, namely ascorbic acid, cysteine, glutathione, 2-mercaptoethanol, potassium metabisulfite at 0.5 mM level. Sodium chloride showed very little inhibition effect on Ginkgo biloba leaves PPO. Lineweaver-Burk analysis of inhibition data revealed that the inhibition by cysteine, 2-mercaptoethanol, potassium cyanide was competitive with ki values of $1.1\;{\times}\;10^{-5}M,\;2.4\;{\times}\;10^{-5}M,\;8\;{\times}\;10^{-5}M$, respectively. Among the divalent cations, $Cu^{2+}ion$ was a strong activator on PPO and $Mn^{2+}ion$ was little or no effect on PPO activity $Ni^{2+}ion$ was an inhibitor on PPO.

• Applied Biological Chemistry
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• v.46 no.3
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• pp.176-182
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• 2003

An alkaline fibrinolytic protease-producing bacteria was isolated front Korean traditional soy sauce and identified as Bacillus subtilis K7 from the results of analyses of its morphological and physiological properties, $API^{\circledR}$, and Biolog system. The enzyme was purified by 75% ammonium sulfate fractionation, QAE-Sephadex anion and SP-Sephadex cation exchange column chromatography and Sephadex G-100 gel filtration. The specific activity of the purified enByme was 233.9 unit/mg protein and the yield of enzyme was 3.8%. The homogeneity of the purified enzyme was confirmed by polyacrylamide gel electrophoresis. Molecular mass of the enzyme was estimated about 21,500 Da by SDS-polyacrylamide get electrophoresis and gel chromatography. The optimum temperature and pH for the enzyme activity were $40^{\circ}C$ and 9.0, respectively. The enzyme was stable in a pH range of 5.0 to 12.0, and 60% of its activity was lost on heat treatment at $50^{\circ}C$ for 20 min. The activity of the purified enzyme was inhibited by the presence of $Fe^{2+},\;Ag^{2+},\;Cu6{2+}$, iodoacetate, ethylene diamine tetraacetic acid (EDTA), and trans-1,2-diaminocycloheane-N,N,N',N'-tetraacetic acid (CDTA). The results indicates that the enzyme requires a metal ion for its enzymatic activity.

• 한국해양학회지
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• v.25 no.4
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• pp.189-204
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• 1990

In the KODOS (Korea Deep Ocean Study)-89 area, western part of clarion-Clipperton fracture zones in the northeastern equatorial Pacific, magnate nodules and sediments were sampled during the 'Farnella' cruise in Oct., 1989. Bulk chemical and mineralogical analyses have been made on a suit of ferromanganese nodules and sediments to study the origin and distribution pattern of the nodules. The nodules are classified into three groups based on their origin: diagenetic nodules with high Mn/Fe ratio, Cu, Ni, Zn, Mg, todorokite contents and rough surface texture; hydrogenetic nodules with high Fe, Co, vernadite contents and smooth surface texture; and transitional nodules with intermediate characters between diagenetic and hydrogenetic nodules. Study area is divided into four zones according to the origin and abundance of nodules: far north area where nodules are hydrogenetic and intermediate in abundance; north area where nodules are diagenetic and low in abundance; south area where nodules are diagenetic and intermediate in abundance; seamount area where nodules are hydrogenetic and high in abundance. distribution pattern of manganese nodules in the KODOS-89 area seems to be controlled by latitudinal variation of productivity in water column and sea bottom morphology.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.E
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• pp.19-25
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• 1998

Adsorption characteristics of DMMP and IMPF were investigated using dynamic adsorption method. Adsorbate vapor was forced to Pass at fixed flow rate of 4 mg/I through Cu Cr impregnated activated carbon column at several different flow velocities until the effluent concentrations exceeded 4.0$\times$10$^{-5}$ mg/I. The kinetic adsorption capacity, adsorption kinetic constant, and critical bed weight of the activated carbon were determined for DMMP and IMPF vapors by plotting breakthrough time as a function of carbon weight. A mathematical expression was deduced from our experimental data to represent the relationships between kinetic adsorption capacity and flow velocity. According to our experimental results, the lifetime of DMMP was longer than that of IMPF under the same conditions. Their relationship can be expressed empirically as follows: Tb(DMMP) ＝ 0.9825$\times$Tb(IMPF)-15.368

• Journal of Microbiology and Biotechnology
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• v.6 no.1
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• pp.1-6
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• 1996

A bacterial strain NS70 producing an alkaline protease was isolated from soil samples taken near a hot spring and identified as Bacillus licheniformis by its morphological and physiological properties and cellular fatty acid analysis. The isolated alkaline protease was purified by ammonium sulfate fractionation, DEAE-, CM-, and Phenyl-Sepharose column chromatography. The molecular weight of the purified enzyme was estimated to be 32, 000 Da by sodium dodecylsulfate polyacrylamide gel electrophoresis. Its optimal pH and temperature for proteolytic activity against Hammarsten casein were 12 and $65^{\circ}C$, respectively. The enzyme was stable at alkaline pH range from 6.0 to 12.0, and fairly stable up to $65^{\circ}C$. The enzyme was inhibited by phenylmethylsulfonyl fluoride but not by EDTA and N-ethylmaleimide indicating that the enzyme is serine protease. Enzyme activity was markedly inhibited by $Hg^{2+}$ and $Cu^{2+}$. Autolytic phenomena were observed on purified protease NS70 but autolysis was reduced by the addtion of $Ca^{2+}$ ion or bovine serum albumin.

• YAKHAK HOEJI
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• v.52 no.2
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• pp.93-100
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• 2008

A liquid chromatographic method with tandom spectrometric detection (LC/MS/MS) for the simultaneous determination of doxifluridine and its active metabolite, 5-fluorouracil (5-FU) was developed over the concentration range of $5{\sim}2000$ ng/ml, respectively. Doxifluridine, 5-FU and internal standard, 5-chlorouracil (5-CU), were extracted from liver and intestine tissue via protein precipitation. Acetonitrile was used as the extraction solvent and the supernatant was evaporated and reconstructed in mobile phase. Optimum chromatographic separation was achieved on a Agilent Zorbax $C_{18}$ ($100\;mm{\times}2.1\;mm$, $3.5\;{\mu}m$) column with mobile phase run in isocratic with methanol : water (20 : 80, v/v). The flow rate was 0.2 ml/min with total cycle time of 5 min. The lower limit of quantification was validated at 5.0 ng/ml of liver and intestine tissue, for both doxifluridine and 5-FU, respectively. The intra-day and inter-day precision and accuracy of quality control (QC) samples were <11% coefficient of variation and <7% relative error from theoretical concentration for both analytes. In addition, the special designed stability study was performed, because the metabolism of doxifluridine occurs spontaneously even in ice bath for monkey liver. The stability of doxifluridine in liver and intestine of monkey and beagle dog was compared. It was found that bioanalytical validation could not be performed for the monkey liver; however, beagle dog's liver has relatively low speed of metabolism compared to monkey liver and instead of monkey liver, beagle dog's liver could be used for the validation. Bioanalytical validation could be performed in monkey intestine. Eventually, this developed method for liver and intestine will be useful in support of the toxicokinetic and pharmacokinetic studies of doxifluridine and 5-FU.

• Bulletin of the Korean Chemical Society
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• v.26 no.10
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• pp.1529-1532
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• 2005

A simple and cost effective method for separation and preconcentration of Ag(I) at the $10^{-7}\;mol\;L^{-1}$ level in the environmental and mineral samples is present. The method is based on the flotation of Ag(I)-iodide complex as an ion-associate with ferroin in pH of 4 from a large volume of an aqueous solution (500 mL) using nheptane. The floated layer was then dissolved in dimethylsulfoxide (DMSO) for the subsequent spectrophotometric determination. Beer's law was obeyed over a range of 2.0 ${\times}$ $10^{-7}$-4.0 ${\times}$ $10^{-6}$ mol $L^{-1}$ with the apparent molar absorptivity of 2.67 ${\times}$ $10^5$ L $mol^{-1}\;cm^{-1}$. The detection limit (n = 5) was 4 ${\times}$ $10^{-8}$ mol $L^{-1}$, and RSD (n = 5) obtained for 2.0 ${\times}$ $10^{-6}$ mol $L^{-1}$ of Ag(I) was 2.2%. The interference effects of a number of elements was studied and found that only $Hg^{2+}$ at low concentration, and $Pb^{2+}$, $Cd^{2+}$, $Cu^{2+}$, and $Fe^{3+}$ ions at moderately high concentrations were interfered. To overcome on these interference effects, the solution was treated with EDTA at a buffering pH of 4 and passed through a column containing Amberlite IR-120 ionexchanger resin, just before the flotation process. The proposed method was applied to determine of Ag(I) in a synthetic waste water, a photographic washing sample and a geological sample and the results was compared with those obtained from the flame atomic absorption spectrometry. The results were satisfactorily comparable with together, so that the applicability of the proposed method was confirmed in encountering with the real samples.