• Journal of the Korean Society of Food Science and Nutrition
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• v.15 no.2
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• pp.158-164
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• 1986

Polyphenol oxidase in apple (Golden Delicious) was extracted, partially purified and its properties were found as follows; Polyphenol oxidase showed optimum pH for activity at 6.5 and optimum temperature at $30^{\circ}C$ and high affinity to o-diphenol compounds. Cysteine, ascorbic acid and sodium metabisulfite appeared to be most effective inhibitors. EDTA showed a slight inhibition. During the enzyme was kept in test tube at $4^{\circ}C\;and\;20^{\circ}C$ for a week, polyphenol oxidase activity decreased sharply during the first four days at $20^{\circ}C$, then decreased slowly as the storage was prolonged. At $4^{\circ}C$, the polyphenol oxidase activity appeared to be relatively stable during the first two days before activity began to decline sharply. Polyacrylamide disc gel electrophoresis indicated four bands with polyphenol oxidase activity. Three bands and one band of the active bands were observed after heating for 1hr at $60^{\circ}C\;and\;70^{\circ}C$ respectively. The enzyme activity was observed 40% after treatment at $60^{\circ}C$ and 5% after treatment at $70^{\circ}C$. Therefore, no difference in the thermal stability was observed between active bands and the enzyme activity.

• Journal of the Korean Chemical Society
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• v.54 no.5
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• pp.567-572
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• 2010

5,10-Methenyltetrahydrofolate synthetase from chicken liver was purified through 30-70% ammonium sulfate fractionation, Q Sepharose Fast Flow anion exchange and Source 15Phe hydrophobic interaction chromatography. Specific activities of cell extract, ammonium sulfate, Q Sepharose Fast Flow and Source 15Phe were 0.0085, 0.031, 0.80 and 1.27 U/mg, respectively. Purification fold activities of cell extract, ammonium sulfate, Q Sepharose Fast Flow and Source 15Phe were 1, 3.7, 94.1 and 149.4, respectively. HPLC gel permeation chromatography and SDS-polyacrylamide electrophoresis experiments indicated that the enzyme is a monomeric protein with a molecular weight of 22.8 kDa. Km for 5-methyl THF and Mg-ATP were $7.1\;{\mu}M$ and $63\;{\mu}M$, respectively. Optimum temperature and pH were $30^{\circ}C$ and 6.0, respectively. The data for metal ion specificity and stoichiometry showed that the maximum activity was obtained with a 1:l. ratio of $Mg^{2+}$. The ATP and Km values increased in the order of MgATP, MgCTP, MgUTP and MgGTP, and the maximum activities also decreased in the same order, indicating MgATP as the most efficient substrate. The enzyme was chemically modified only by tetranitrometane and 1-ethyl-3-(3-dimethyl aminopropyl)-carbodiimide, indicating that tyrosine and carboxylate are present in the active site.

• Korean Journal of Microbiology
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• v.45 no.4
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• pp.324-331
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• 2009

MK1 strain, an obligate aerobic heterotrophic bacterium isolated from the rotten tissue of Neungee mushroom (Sarcodon aspratus), produces a copious amount of exopolysaccharide (EPS), which could evoke macrophage activation. Investigations on optimal culture conditions of MK1 and physical properties of MK1 EPS were made. Glucose, galactose, fructose, and sucrose supported well growth of MK1, but potato starch and dextrin did not. However, lactose seemed to be a less favorable carbon source. Optimal growth of MK1 was obtained at pH 7.0, $30^{\circ}C$, and 200 rpm with 2% glucose, and 0.2~0.05% $(NH_4)_2SO_4$. $EPS_{opt}$ obtained from an optimal growth condition constituted of carbon (37.1%), nitrogen (2.2%), oxygen (49.3%), and hydrogen (6.4%), but no sulfur. Paper chrogromatogram of the acid-hydrolysate of $EPS_{opt}$ suggested that MK1 EPS seemed to be hetropolysaccharide composed of a few number of monosaccharides including amino- and acidic-sugars. Its molecular mass determined by SDS-polyacrylamide gel electrophoresis varied from 14.8 to 47.9 kDa. Physical properties of $EPS_{glu}$ obtained from cell grown in glucose medium, such as relative viscosity ($_{rel}$) and crystalline morphology were rather affected by pH of the growth medium. Relative viscosity ($_{rel}$) of exopolysaccaride (0.1 g/ml) harvested from cells grown at medium pH ranging from 6.0 and 7.5 was 1.23 and 1.39, respectively. The freeze-dried exopolysaccharide obtained at low pH (6.0 and 6.5) was fine crystaloid and water-soluble, whereas those obtained at high pH (7.0 and 7.5) was rather gluey and less water-soluble.

• Microbiology and Biotechnology Letters
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• v.48 no.2
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• pp.215-222
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• 2020

The marine microorganism PX-1, which can hydrolyze xylan, was isolated from coastal sea water of Jeju Island, Korea. Based on the 16S rRNA gene sequence and chemotaxonomy analysis, PX-1 was identified as a species of the genus Aestuariibacter and named Aestuariibacter sp PX-1. From the culture broth of PX-1, an extracellular xylanase was purified to homogeneity through ammonium sulfate precipitation and subsequent adsorption chromatography using insoluble xylan. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration chromatography estimated the molecular weight of the purified putative xylanase (XylA) as approximately 64 kDa. XylA showed xylanase activity toward beechwood xylan, with a maximum enzymatic activity at pH 6.0 and 45℃. Through thin-layer chromatographic analysis of the xylan hydrolysate produced by XylA, it was confirmed that XylA is an endo-type xylanase that decomposes xylan into xylose and xyloligosaccharides of various lengths. The K_m and V_max values of XylA for beechwood xylan were 27.78 mM and 78.13 μM/min, respectively.

• Applied Biological Chemistry
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• v.22 no.4
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• pp.191-197
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• 1979

${\beta}-Tyrosinase$ was purified and crystallized from cells of Escherichia intermedia A-21 grown in a medium supplemented with 0.2% L-tyrosine. Molecular weight of its subunit, Km value and absorption spectra were determined. Crystallization methods were also studied to eliminate any unnecessary procedures. The results obtained were as follows: 1. The purification procedure included ammonium sulfate fractionation, dialysis against potassium phosphate buffer, pH 6.0 and pH 7.0, and DEAE-Sephadex column chromatography. In the column chromatography, 11 mg of protein was applied per ml of DEAE-Sephadex for efficiency. 2. Steps of protamine sulfate treatment and Sephadex G-150 gel filtration could be eliminated for this enzyme from the known procedures. 3. The purified enzyme was dissolved in 0.01M potassium phosphate buffer containing 2-mercaptoethanol, with a concentration of 20mg/ml. Crystalline enzyme, which appears as hexagonal rods, was obtained by adding solid fine powdered ammonium sulfate to the enzyme solution. 4. Absorption maxima of the enzyme appeared at 340 and 430nm when associated with pyridoxal phosphate. 5. Km value of the enzyme for L-tyrosine was $2.31{\times}10^{-4}M$ and the molecular weight of its subunit was determined by SDS-polyacrylamide electrophoresis to be approximately 50,000.

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.3
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• pp.249-255
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• 1995

This study was conducted to investigate the effects of some soil conditioners, such as polyacrylamide(PAM), polyvinylalcohol(PVA) and Bitumen emulsion, on aggregate formation and stability, wetting angle, sorptivity and penetrability of the soil with different textures : sand, sandy loam, loam and clay loam. A pot experiment was carried out to find out the effect of treatment on the germination and growth of lettuce with three textures : sand, sandy loam and silt loam. Soil aggregates larger than 2mm in untreated soils at dry condition were naught in sand, 45% in sandy loam, 80% in loam and 90% in clay loam. Treatments of soil conditioners tended to increase the occurrence of soil aggregate larger than 2mm, which were 20~25% in sand, 55~75% sandy loam, but not affected greatly aggragate occurence in loam and clay loam. The aggregate instability was decreased by the soil conditioner treatment. The wetting angles of the soils were greatly changed by hydrophobic of Bitumen, but those were changed slightly by PVA and PAM application. The sorptivity and penetrability data indicated that the effects of different materials on these parameters differed depending upon soil texture. Application of PVA and PAM were no effect exceptive in sand. Application of Bitumen revealed that water movement was not showed in all soils. The germination rate, root weight and top plant weight of lettuce were increased in all soils by PAM treatment as compared to untreated soils. Particularly the greater effect was occurred in sand soil than in sandy loam and silt loam. PAM increased greatly the moisture content and air phase of soils.

• Journal of Life Science
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• v.18 no.4
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• pp.454-460
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• 2008

This study was carried out to demonstrate morphological, cytological and molecular evidence for intersubgeneric $F_1$ hybrid between Glycine tomentella and G. max cv. ‘Baemkong’. Morphological features of $F_1$ plant for pistil and stamen, flower color and growth habit showed intermediate type between G. tomentella and G. max cv. ‘Baemkong’. Chromosome number of $F_1$ plant was 2n=39, which explained the evidence of $F_1$ hybrid between G. tomentella (2n=38) and G. max cv. ‘Baemkong’ (2n=40). Polyacrylamide isoelectric focusing pattern for esterase and peroxidase also showed that the $F_1$ plant was true $F_1$ hybrid between G. tomentella and G. max cv. ‘Baemkong’. From RAPD analysis, we identified that 62 primers showing bands in $F_1$ hybrid had both bands from G. tomentella and G. max cv. ‘Baemkong’, which suggested that this was true $F_1$ hybrid. Based on our results from morphological, cytological and molecular analyses, we suggest that the $F_1$ plant was true intersubgeneric hybrid between G. tomentella and G. max cv. ‘Baemkong’. Our results still remain us further study to recover fertility of $F_1$ hybrids. The occurrence of maternal and/or paternal inheritance in $F_1$ hybrid from intersubgeneric cross between G. tomentella and G. max cv. ‘Baemkong’ need to be explained.

• Korean Journal of Food Science and Technology
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• v.32 no.5
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• pp.1158-1167
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• 2000

To produce ${\beta}-cyclodextrin({\beta}-CD)$, a cyclodextrin glucanotransferase(CGTase) producing Aspergillus sp. CC-2-1 was isolated from soil. The enzyme was purified and its enzymological characteristics were investigated. It was found that production of CGTase reached to the maximum when the wheat bran medium containing 0.1% albumin, 2% $(NH_4)_2S_2O_8$, 2% soluble starch and 0.2% $KH_2PO_4$ was cultured for 5 days at $37^{\circ}C$. The purity of CGTase was increased by 13.14 folds after DEAE-cellulose ion exchange chromatography and Sephadex G-100, G-150 gel filtration and the specific activity was 172.14 unit/mg. Purified enzyme was confirmed as a single band by the polyacrylamide gel electrophoresis. The molecular weight of CGTase was estimated to be 27,800 by Sephadex G-100 gel filtration and SDS-polyacrylamide gel electrophoresis. The optimum pH and temperature for the CGTase activity were 9.0 and $80^{\circ}C$, respectively. The enzyme was stable in pH $8.0{\sim}11.0$ at $60{\sim}80^{\circ}C$. The activity of purified enzyme was activated by $K^+,\;Cu^{2+}$ and $Zn^{2+}$. The activity of the CGTase was inhibited by the treatment with 2,4-dinitrophenol and iodine. The result suggests that the purified enzyme has phenolic hydroxyl group of tyrosine, histidine imidazole group and terminal amino group at active site. The reaction of this enzyme followed typical Michaelis-Menten kinetics with the $K_m$ value of 18.182 g/L with the $V_{max}$ of 188.68 ${\mu}mole/min$. The activation energy for the CGTase was calculated by Arrhenius equation was 1.548 kcal/mol.

• Journal of Yeungnam Medical Science
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• v.7 no.1
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• pp.39-50
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• 1990

The one event on signalling mechanism is the cleavage by adenyl cyclase of ATP into second messenger, cyclic AMP. The other transfer system of inositol metabolism. it is widely recognized that hydrolysis of the minor membrane lipid phosphoinositide bisphosphate($PIP_2$) initiated by occupation of certain receptors and catalyzed by phospholipase C, lead to toe generation of the two intracellular messengers, inositol triphosphate($IP_3$) and diacylglycerol(DG). $IP_3$ is converted to inositol tetrakisphosphate($IP_4$) by $IP_3$ kinase. In the present study, it is that purification of calmodulin is used by phenyl-Sepharose CL-4B chromatography. it's molecular weigh, 17.000 in SDS-polyacrylamide gel electrophoresis. In order to observe the affinity between calmodulin (CaM)-Affigel 15 and $IP_3$ kinase, and isolated $IP_3$ kinase, was applied in CaM-Affigel with $Ca^{2+}$ equilibirum buffer and EGTA equilibirum buffer. We compared with binding and elution effect of $IP_3$ kinase in several condition of buffer. In affinity of binding. $Ca^{2+}$ equilibrium buffer was in the most proper condition. and elution, CaM/$Ca^{2+}$ buffer(CE1 10.36, CE2 12. 76pM/min/mg of protein) was effected much more than EGTA buffer(E2 1.48, E3 2.43pM/min/mg of protein), but CaM/$Ca^{2+}$ stimulate the activity of $IP_3$ kinase. And then, several detergents such as sodium deoxycholate, tween 20. cholic acid, polyethylene glycol, chaps were applied. The 0.2% chaps buffer(E2 23.19, E3 8.05pM/min/mg of protein) was the most effective in elution of $IP_3$ kinase.

• Journal of Microbiology and Biotechnology
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• v.6 no.2
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• pp.86-91
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• 1996

Thermostable $\beta$-mannanase from Bacillus sp. YA-14 was purified by acetone precipitation, CM-cellulose, Sephadex G-100 and hydroxyapatite column chromatography from culture supernatant. The final enzyme preparation appeared to be homogeneous on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). $\beta$-Mannanase appeared to be a monomeric protein with a molecular weight of 67, 000 daltons. The optimal pH and temperature of the enzyme reaction were pH 6.0 and $75^{\circ}C$ , respectively. The enzyme was stable at a pH range of 6.0 to 9.0 and at temperatures between 45 and $85^{\circ}C$. The kinetic constants of $\beta$-mannanase as determined with a galactomannan (locust bean) as substrate were a Vmax of 25 unit/ml and a Km of 1.1 mg/ml. The enzyme had only limited activity on galactomannan substrate. It was suggested that mg $\beta$-mannanase activity is limited by the number of branched $\alpha$-galactose residues.