• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.1
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• pp.50-56
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• 2002

The $\beta$-galactosidase was purified from the internal organs of edible snail by fractionation with ammonium sulfate, ion exchange chromatography on DEAE-Sephadex, Mono Q HR 5/5 and gel filtration on Sephacryl S-200. Superose 12 HR 10/30 chromatography. The specific activity of the purified $\beta$-galactosidase was 18.8 units/mg protein with 31.3 purification fold from crude extract. The $\beta$-galactosidase had native molecular weight of 144,000 dalton and was composed of two subunits of 72,000 dalton. The isoelectric point of the enzyme was determined 4.1. This enzyme was the most active at pH 3.0 and 6$0^{\circ}C$, and was stable in the pH range 2.0~8.0 and below 5$0^{\circ}C$. The enzyme was inhibited by metal ions and sugars such as fructose, glucose, galactose, maltose and xylose.

• BMB Reports
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• v.32 no.3
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• pp.239-246
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• 1999

A tripeptidase (PepT) was purified to homogeneity from Bacillus subtilis through four sequential chromatographies including DEAE-Sepharose ion exchange, hydroxylapatite, mono-Q FPLC ion exchange, and Superose-12 FPLC gel filtration. The apparent molecular mass of the enzyme was 49,200 Da and 51,400 Da as determined by sodium dodecylsulfatepolyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration chromatography, respectively, and the enzyme exists in a monomeric form. The physicochemical properties of the enzyme were as follows: optimum pH at 7.5, optimum temperature at $60^{\circ}C$, and pI at 4.9. The $K_m$ and $V_{max}$ values of the enzyme were 4.3 mM and 2.5 mmol/min/mg, respectively, with MetAla-Ser as substrate. The B. subtilis PepT requires $Co^{2+}$ ion(s) for activation, while it is inactivated by EOTA and 1,10-phenanthroline, suggesting that it is a metalloprotein. The enzyme was not inhibited by any of serine protease, aspartic protease, or leucine aminopeptidase inhibitors. The enzyme showed comparable activities towards four different substrates including Met-Ala-Ser, Leu-Gly-Gly, Leu-Ser-Phe, and Leu-Leu-Tyr. The amino terminal sequence of PepT determined by Edman degradation was found to be MKEEIIERFTTYVXV and turned out to be identical to that of PepT deduced from a cloned B. subtilis pepT.

• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.1011-1017
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• 2001

Streptomyces sp. Y-110 cytochrome P-450, induced by the addition of compactin -Na into the culture medium, was purified from the cell extract to apparent homogeniety, mainly by DEAE-Sepharose, hydroxyapatite, and Mono Q column chromatyography. The sepcific activity of purified enzyme on its substrate, compactin-Na, was determined to be 15 nmol of pravastatin per mg protein. The molecular mass of this enzyme on SDS-PAGE was $37{\pm}0.5$ kDa, pI was 4.5, and its CO difference spectrum showed maximum absorption peaks at 452 and 550nm, respectively. The N-terminal amino acid sequence was determined to be Met>Thr>Cys>Thr>Pro>Val>Thr>Val>The>Gly>Ala>Ala>Gly>Gln>Ile>Gly>Tyr>Ala>Leu. Its apparent $K_m$ on compactin-Na was $1.294{\mu}M{\cdot}min^-1,\;and\;V_{max}\;was\;1.028{\mu}M{\cdot}min^-1$. The maximum substrate concentration ($K_s$) for reaction was $270 {\mu}M$and thus $1/[K_s]$ was $3.7{\mu}M$. These physicochemical characteristics and kinetic behavior of this enzyme were compared and shown to be different from those of Streptomyces cytochrome P-450 enzymes reported, suggesting that this enzyme may be an additional member of the Streptomyces cytochrome P-450 family.

• Korean Journal of Environment and Ecology
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• v.5 no.1
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• pp.9-24
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• 1991

To elucidate the actual vegetation of Nature Ecology Conservation area in Mt. Chiri, forest communities were classified phytosoclologically by species composition and phsiognomy. There included 13 forests ranging from temperate-cool zone to sub-cold zone in the surveyed area. Actual vegetation map was drawn on the basis of classified forest communities. The forest communities classified in the area were summarized as follows ; 1. Querus serrata community 2. Carpinus laxiflora community 3. Q. serrata-C. laxiflora community 4. Stewartia koreana community 5. Acer mono community 6. Carpinus cordata community 7. Fraxinus mandshurica community 8. Carpinus tschonoskii community 9. Pinus densiflora community 10. Querus mongolica Community 1) Rhododendron schlippenachii subcommunity 2) Lenedeza maximowiczii subcommunity 11. Abies nephrolepis community 12. Abies koreana community 1) Querus mongolica subcommunity 2) Pinus koraienis subcommunity 13. Rhododendron schlippenbachii community Among above forest communities, Querus serrata community distributed from 700m to 1,000m in the ridges, Carpinus laxiflora community in the valleys, Quercus mongolica community from 1,000m to 1,400m, and Abies koreana community and Abies nephrolepis community from 1,400m to 1,700m.

• Journal of Life Science
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• v.17 no.4 s.84
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• pp.581-586
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• 2007

Staphylococcus epidermidis is a coagulase-negative, gram-positive bacterium that normally inhabits the human skin. S. epidermidis is also known to be an opportunistic pathogen in infections of various indwelling medical devices. This report describes purification and characterization of the urease of S. epidermidis urease, which may act as a virulence factor. The urease from S. epidermidis was purified 1,127 fold by using DEAE-Sepharose, Phenyl-Sepharose, Mono-Q and Superdex HR200 column chromatography. The specific activity of the purified enzyme was 993.8 U/mg. Michaelis constant($K_m$) of the enzyme was estimated to be 8.5 mM urea by using Lineweaver-Burke double reciprocal plot. The native molecular weight of the urease was shown to be 255 kD by using Superose 6HR gel filtration chromatography and the purified enzyme contained 2.2 nickel ions per catalytic unit. The overall stoichiometry of the enzyme subunits appears to be $(\alpha\beta\gamma)_3$, which is consistent with the enzymes from other bacteria sources.

• Korean Journal of Environment and Ecology
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• v.21 no.2
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• pp.113-119
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• 2007

To investigate the vegetation structure at Orimok of Hallasan national park, 28 plots$(2,000m^2)$ were surveyed by random sampling method. Carpinus tschonoskii was a major woody species in the studied area in Orimok, and Quercus gorsseserrata, Quercus serrata, and Quercus mongolica were partly occupied. High negative correlations were shown between C. tschonoskii and Ilex macropoda, Lindera erythrocarpa, Quercus mongolica Comus walteri and Symplocos coreana, and relatively high positive correlations were proved to exist between Acer pictum var. mono and Carpinus cordata, Quercus gorsseserrata Ilex macropoda and Lindera erythrocaypa, Q. mongolica Abies nephrolepis and Prunus sargentii, Kalopanax septemlobus Taxus cuspidata and Symplocos coreana. Species diversity(H') was 0.771, and it was relatively low numerical value compared to that of other national parks.

• Korean Journal of Plant Resources
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• v.22 no.5
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• pp.389-393
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• 2009

Regional distribution of mistletoe (Viscum album var.coloratum) and its habitual environments were investigated in order to obtain the basal data on the artificial propagation to cope with its increasing consume for medicine. Mistletoes inhabited throughout the overall region of the South Korea investigated. They were parasitic mainly to the Quercus spp. including Q. serrata and rarely to the Castanea crenata var. dulcis, Prunus serrulata var. spontanea, Alnus japonica, and Pyrus pyrifolia, etc. Mistletoes were not observed on the conifers such as Pinus densiflora and Pinus koraiensis and some deciduous broad-leaved trees species such as Zelkova serrata, Diospyros kaki, Acer mono, Acer palmatum, and Morus alba. Their habitats were located from zero to 1,200 m above sea level nevertheless the direction or slope of the mountains, suggesting that artificial propagation can be carried out nation widely to the well-grown parasite tree species. Parasitic specificity related to the physical and chemical characteristic of the epidermal tissues will be studied further.

• Korean Journal of Plant Resources
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• v.22 no.5
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• pp.412-424
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• 2009

The flora and vegetation of Chuncheon area were investigated from March, 2006 to September, 2008. Vascular plants of investigated regions were composed of 118 families, 496 genera, 894 species, 2 subspecies, 132 varieties, and 38 forms, totally 1,066 taxa, and the Pteridophyta index (Pte-Q) was 1.17. Forty two taxa including endemic genus Hanabusaya and Echinosophora among the 1,066 taxa were Korean endemic. Thirty three rare and endangered plants and 119 specially designated plants by Ministry of Environment were also investigated. The naturalized plants were 71 taxa, and percent of naturalized plant species were 6.66%. The vegetation of Chuncheon area were classified into five communities such as Quercus mongolica community, Pinus densiflora-Quercus mongolica community, Quercus mongolica-Acer mono community, Quercus mongolica-Quercus variabilis community and Quercus mongolica-Betula davurica community.

• Journal of Microbiology and Biotechnology
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• v.21 no.3
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• pp.256-262
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• 2011

A 20.9-kDa metalloprotease was isolated from dried fruiting bodies of the wild basidiomycete mushroom Lepista nuda. The N-terminal amino acid sequence of the protease was seen to be ATFVLTAATNTLFTA, thus displaying no similarity with the sequences of previously reported metalloproteases. The protease was purified using a procedure that entailed ion-exchange chromatography on CM-Cellulose, Q-Sepharose, and Mono S, and FPLC-gel filtration on Superdex 75. The protease functioned at an optimum pH of 7.0 and an optimum temperature of $50^{\circ}C$. It was also noted that the protease demonstrated a proteolytic activity of 1,756 U/mg toward casein. The $K_m$ of the purified protease toward casein was 6.36 mg/ml at a pH of 7.0 and with a temperature of $37^{\circ}C$, whereas the $V_{max}$ was 9.11 ${\mu}g\;ml^{-1}\;min^{-1}$. The activity of the protease was adversely affected by EDTA-2Na, suggesting that it is a metalloprotease. PMSF, EGTA, aprotinin, and leupeptin exerted no striking inhibitory effect. The activity of the protease was enhanced by $Fe^{2+}$, but was curtailed by $Cd^{2+}$, $Cu^{2+}$, $Hg^{2+}$, $Pb^{2+}$, $Zn^{2+}$, and $Fe^{2+}$ ions. The protease also exhibited inhibitory activity against HIV-1 reverse transcriptase with an $IC_{50}$ value of 4.00 ${\mu}M$. The $IC_{50}$ values toward hepatoma Hep G2 and leukemia L1210 cells in vitro were 4.99 ${\mu}M$ and 3.67 ${\mu}M$, respectively.

• Journal of Microbiology and Biotechnology
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• v.20 no.10
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• pp.1378-1385
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• 2010

A novel agarolytic bacterium, KY-YJ-3, producing extracellular agarase, was isolated from the freshwater sediment of the Sincheon River in Daegu, Korea. On the basis of Gram-staining data, morphology, and phylogenetic analysis of the 16S rDNA sequence, the isolate was identified as Cellvibrio sp. By ammonium sulfate precipitation followed by Toyopearl QAE-550C, Toyopearl HW-55F, and MonoQ column chromatographies, the extracellular agarase in the culture fluid could be purified 120.2-fold with a yield of 8.1%. The specific activity of the purified agarase was 84.2 U/mg. The molecular mass of the purified agarase was 70 kDa as determined by dodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimal temperature and pH of the purified agarase were $35^{\circ}C$ and pH 7.0, respectively. The purified agarase failed to hydrolyze the other polysaccharide substrates, including carboxymethyl-cellulose, dextran, soluble starch, pectin, and polygalacturonic acid. Kinetic analysis of the agarose hydrolysis catalyzed by the purified agarase using thin-layer chromatography showed that the main products were neoagarobiose, neoagarotetraose, and neoagarohexaose. These results demonstrated that the newly isolated freshwater agarolytic bacterium KY-YJ-3 was a Cellvibrio sp., and could produce an extracellular ${\beta}$-agarase, which hydrolyzed agarose to yield neoagarobiose, neoagarotetraose, and neoagarohexaose as the main products.