• 미생물학회지
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• 제18권1호
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• pp.7-14
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• 1980

A thermostrable ${\beta}-galactosidase$ (${\beta}-galactoside$ galactohydorlase, EC 3.2.1.23) was inducible in Bacillus coagulans by lactose and D-glactose. The enzyme was purified 87 fold, and the optimum temeprature and pH for actiivity were determined to be $60^{\circ}C$ and pH 7.5, respectively. Kinetic determinations at $55^{\circ}C$ established a Km of 3.3mM for the chromogenic substrate onitorphenyl ${\beta}-D-galactopyranoside$ (ONPG). Galactose and lactose were competitive inhibitors with Ki of 6.1mM and 4.9mM, respectively. The enzyme ws relatively thermostable. The crude enzyme was inactivated about 20% after 20 min of exposure at $60^{\circ}C$ and the purified was about 50%. Maximal enzyme activity required $Mn^{++}$, and for the thermal stabilization $Fe^{++}\;and\;Ca^{++}$ were necessary.

• 한국식품저장유통학회지
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• 제5권1호
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• pp.13-21
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• 1998

Korean medicinal herb extracts(KMHE) were applied to the preservation of greenhouse produce in order to prove their effectiveness. KMHE showed remarkable antimicrobial effects against Bacillus cereus, Peudomonas syringae, and Corynebacterium xerosis causing the postharvest decay of greenhouse produce. Among KMHE the extracts of Rheum palmatum L. and Coptis chinensis Franch most obviously inhibited the growth of microorganims causing the Postharvest decay of greenhouse produce, which destroyed to undetectable levels when treated with more than 500ppm of KMHE. The activities of KMHE were stable in the wide spectrum of pH and temperature. Direct visualization of microbial cells by using both transmission electron microscope and scanning electron microscope showed microbial cell membrane the function of which was destroyed by treating with the dilute solutions of KMHE. This change of cellular membrane permeability could be identified in the experiment that O-nitrophenyl-$\beta$-D-galactopyranoside(ONPG), the artificial substrate of $\beta$-galactosidase, was hydrolyzed in the presence of KMHE, indicating that the membrane was perturbed by KMHE.

• 생약학회지
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• 제37권3호
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• pp.125-129
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• 2006

The chromatographic separation of n-BuOH extract of the aerial parts of Prunus padus (Rosaceae) led to the isolation of two cerebrosides, and six phenolic compounds. Their structure were identified to be pinelloside (1), soyacebroside I (2), $quercetin-3-O-{\beta}-D-galactopyranoside$ (3), nudiposide (4), (+)-isolarisiresinol $9'-O-{\beta}-D-xylopyroanoside$ (5), khaephuoside A (6) and icariside F2(7) by physicochemical and spectroscopic methods. The compounds $1,5{\sim}7$ are first isolated from the genus Prunus.

• 생약학회지
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• 제25권2호
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• pp.121-131
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• 1994

Two kinds of new lectins, CATL-I and CATL-II, were partially purified from the intestine of Chlorostoma argyrostoma turbunatum by physical saline extraction, salt fractionation, ion exchange chromatography and gel filtration. CATL-I and CATL-II were purified 39.4 and 15.8 fold with a yield of 8.8 and 7.4%, respectively. On polyacrylamide gel electrophoresis, CATL-I demonstrated one major and one minor bands. This lectin agglutinated human and other animal erythrocytes nonspecifically and also agglutinated murine splenic lymphocytes. Carbohydrate specificity of the lectins was determined by inhibition of the agglutinability by methyl-${\alpha}-_D$-galactopyranoside and $_L-rhamnose$ at a final concentration of 6 mM. The lectins contained relatively high amounts of acidic amino acids, but the contents of sulfur containing amino acids were very low or was not estimated. Immunochemical studies were carried out to identify some properties of marine animal lectins.

• Biotechnology and Bioprocess Engineering:BBE
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• 제2권2호
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• pp.86-89
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• 1997

Epidermal growth factor(EGF) known as a urgastrone is a powerful mitogen with a wide variety of possibilities for medical usages. A mature EGF coding region was isolated from human prepro-EGF sequence by a conventional PCR and cloned into pQE vector in which the gene product was supposed to be expressed with 6$\times$His tag for the subsequent purification. The recombinant mature EGF was expressed in M15[Rep4], an Escherichia coli host strain, in amount of 30-40% of total proteins pressent in E. coli extract by the addition of isopropylthio-$\beta$-galactopyranoside (IPTG). The recombinant EGF purified using a Ni2+-NTA affinity colume chromatography was active in its ability to induce phosphorylation on tyrosine residues of several substrate proteins when murine NH3T3 and human MRC-5 fibroblast cells were stimulated with it. This work may provide the basic technology and information for the production of recombinant EGF.

• 생약학회지
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• 제27권3호
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• pp.178-183
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• 1996

Seven phenolic compounds were isolated from the leaves of Spiraea salicifolia. Their structures were characterized as cinnamic acid, ${\rho}-hydroxy$ cinnamic acid, ${\rho}-methoxy$ cinnamic acid, $1-O-coumaroyl-{\beta}-D-glucopyranose$, $1-O-caffeoyl-{\beta}-D-glucopyranose$, hyperoside and quercetin $3-O-(6'-O-{\alpha}-L-arbinopyranosyl)-{\beta}-D-galactopyranoside$ by chemical and spectroscopic evidence.

• 생약학회지
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• 제43권3호
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• pp.213-216
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• 2012

Six phenolic compounds were isolated from the aerial parts of Bromus japonicus (Gramineae) through repeated column chromatography. Their chemical structures were elucidated as luteolin (1), caffeic acid (2), luteolin-7-O-${\beta}$-D-glucopyranoside (3), quercetin-3-O-${\beta}$-D-galactopyranoside (4), quercetin-3-O-${\beta}$-D-glucopyranoside (5), and luteolin-4'-O-${\beta}$-D-glucopyranoside (6), respectively, by spectroscopic analysis. These compounds were isolated for the first time from this plant.

• 약학회지
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• 제43권3호
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• pp.294-299
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• 1999

From the water fraction of the MeOH extract, three compounds, 1,3,4,5-terrahydroxycyclo-hexanecarboxylic acid 3-(3,4-dihydroxycinnamate) (chlorogenic acid), $quercetin 3-O-{\beta}-D-galactopyranoside(hyperoside)$, and 1 (R)-hydroxy-3,4-seco-lup-4(23), 20(30)-dien-3,$11{\alpha}-olactone-{\alpha}-L-rhamnopyrnaosy(1{\rightarrow}4)-{\beta}-D-glucopyanosy(1{\rightarrow}6)-{\beta}-L-glucopyrnaosyl$ ester (chiisanoside) were isolated and their strutures determinated by $^1H-NMR,{\;}^{13}C-NMR$, IR, and FAB-Mass. Chlorogenic acid and Chiisanoside had been quantitated by HPLC from eight Acanthopanax species per 10 g A. koreanum 19.82, 4.17 mg, A. nambunensis 65.00, 1.86mg, A. chiisanense 27.19, 8.17mg, A. sessiliflorum 7.49, 5.88 mg.

• Bulletin of the Korean Chemical Society
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• 제18권1호
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• pp.44-50
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• 1997

A method of dual-signal generation from two different enzymes was developed and utilized to simultaneously perform dual immunoassays in a single microwell. Two enzymes selected as tracers were horseradish peroxidase (HRP) and β-galactosidase (GAL). 3, 3', 5, 5'-Tetramethylbenzidine (TMB) and chlorophenolred-β-galactopyranoside (CPRG) as chromogenic substrates for the respective enzyme were used. Although the two enzymes showed their maximum activities at distinct pH conditions (pH 5.1 for HRP and 7.5 for GAL), the enzyme reactions were able to be concurrently carried out at pH 5.75 in a dual-substrate solution without signal loss. This performance was achieved by increasing TMB concentration two-fold, introducing potassium salt as activator of GAL reaction, and extending total reaction time 50%. The signal generation method was then used for dual-enzyme immunoassays to detect antibodies with co-immobilized Hepatitis C virus antigens (core and NS5) and a Hepatitis B virus antigen (PreS(2)) in a microwell. Dose-response curves of the assays revealed cooperativity between different antigen-antibody complex formation, which suggested that dual immunoassays can only be used for qualitative screening tests unless the antigens immobilized were spatially separated.

• Journal of Microbiology and Biotechnology
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• 제18권2호
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• pp.287-294
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• 2008

Three amino acid residues (His119, Glu164, and Glu338) in the active site of Thermus caldophilus GK24 ${\beta}$-glycosidase (Tca ${\beta}$-glycosidase), a family 1 glycosyl hydrolase, were mutated by site-directed mutagenesis. To verify the key catalytic residues, Glu164 and Glu338 were changed to Gly and Gln, respectively. The E164G mutation resulted in drastic reductions of both ${\beta}$-galactosidase and ${\beta}$-glucosidase activities, and the E338Q mutation caused complete loss of activity, confirming that the two residues are essential for the reaction process of glycosidic linkage hydrolysis. To investigate the role of His119 in substrate binding and enzyme activity, the residue was substituted with Gly. The H119G mutant showed 53-fold reduced activity on 5mM p-nitrophenyl ${\beta}$-D-galactopyranoside, when compared with the wild type; however, both the wild-type and mutant enzymes showed similar activity on 5mM p-nitrophenyl ${\beta}$-D-glucopyranoside at $75^{\circ}C$. Kinetic analysis with p-nitrophenyl ${\beta}$-D-galactopyranoside revealed that the $k_{cat}$ value of the H119G mutant was 76.3-fold lower than that of the wild type, but the $K_m$ of the mutant was 15.3-fold higher than that of the wild type owing to the much lower affinity of the mutant. Thus, the catalytic efficiency $(k_{cat}/K_m)$ of the mutant decreased to 0.08% to that of the wild type. The $k_{cat}$ value of the H119G mutant for p-nitrophenyl ${\beta}$-D-glucopyranoside was 5.l-fold higher than that of the wild type, but the catalytic efficiency of the mutant was 2.5% of that of the wild type. The H119G mutation gave rise to changes in optima pH (from 5.5-6.5 to 5.5) and temperature (from $90^{\circ}C\;to\;80-85^{\circ}C$). This difference of temperature optima originated in the decrease of H119G's thermostability. These results indicate that His119 is a crucial residue in ${\beta}$-galactosidase and ${\beta}$-glucosidase activities and also influences the enzyme's substrate binding affinity and thermostability.