• Journal of Microbiology and Biotechnology
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• v.6 no.1
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• pp.26-29
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• 1996

The genes coding for the urease of alkalophilic Bacillus pasteurii have been previously cloned and recently sequenced. (You, J. H., B. H. Song, J. H. Kim, M. H. Lee, and S. D. Kim (1995) Molecules and Cells 5, 359-369.) The recombinant Bacillus pasteurii urease expressed in an E. coli HB101 strain was purified 31.2 fold by using combinations of anion-exchange and hydrophobic chromatography followed by Mono-Q chromatography on a FPLC. In spite of the presence of three discrete structural peptide genes in the Bacillus pasteurii urease gene cluster, only one or two enzyme subunits have been observed to date. Here we report for the first time that the recombinant Bacillus pasteurii urease expressed in a E. coli strain consists of three distinct subunits. One large subunit was estimated to be of $M_r$=65, 200 and the two small-subunit peptides are of $M_r$=14, 500 and $M_r$=13, 700, respectively.

• The Korean Journal of Food And Nutrition
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• v.12 no.2
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• pp.184-190
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• 1999

Soybean protein consists of two major components $\beta$-conglycinin and glycinin which together consti-tute 70% of the total seed storage protein at maturity. $\beta$-Conglycinin is trimeric glycoprotein and for-med by the assembly of various combinations of three subunits $\alpha$,$\alpha$' and $\beta$ which have molecular weig-hts of 69,000, 72,000 and 42,000, respectively. Recently $\beta$-conglycinin was identified as powerful LDL lip-oprotein receptor activation hypercholesterolemia and major allergenic proteins. To investigate these reasons we constructed an expression system of cDNA encoding $\alpha$-subunit of $\beta$-conglycinin in Escherichia coli and purified the expressed protein. The pro-$\beta$-conglycinin synthesized in Escherichia coli BL 21 (DE3)comprised approximately 15% of the total bacterial proteins and the expressed protein are formed sol-uble and trimer such as native protein in Escherichia coli cells. The highly expressed protein was purified to homogeneity by salt precipitation with 20~40 % ammonium sulfate ion-exchange chromatography with Q-sepharose and hydrophobic column chromatography with Butyltoyopearl.

• Korean journal of food and cookery science
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• v.18 no.1
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• pp.94-100
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• 2002

The dietary carbohydrates are mainly digested and adsorbed at small intestine. We developed a new food additive as an egg yolk antibody(1gY) against maltase, sucrase and sodium dependent g1ucose cotransporter(SGLT) for the regulation of blood glucose level and weight control. The maltase, sucrase and SGLT were purified from porcine small intestine which is very similar to that of human in physiological characteristics. The purification step contained an ultracentrifugation, ion exchange chromatography and hydrophobic chromatography. The hens were immunized by purified protein and the IgY activities against immunized antigens were determined. This antibody obtained from the immunized hen's egg yolks directly inhibited the activities of maltase and sucrase in vitro. And the IgY delayed and decreased the increment of blood g1ucose level after administration of maltose, sucrose and glucose in rat about 30 to 60%. The results of this study suggest that the IgY inhibiting the carbohydrate digestion could be used as functional food materials for weight control and regulation of blood glucose level in diabetes.

• KSBB Journal
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• v.13 no.6
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• pp.656-661
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• 1998

Hantaan virus belonging to the genus Hantavirus and family Bunyaviridae causes an acute severe illness of human, Haemorrhagic Fever with Renal Syndrome (HFRS). It is a rodent host-borne pathogen and distributed in Asia and Eastern Europe. Hantaviruses have three major antigens, i.e., G1, G2 glycoproteins and nucleocapsid protein (N). Among them, nucleocapsid protein was reported to be the most invaluable antigen as for diagnosis. We have cloned and expressed Hantaan viral nucleocapsid gene in E. coli BL21(DE3). In this study, we have tried to purify the nucleocapsid protein produced by recombinant E. coli, and could attained a purity of >90% by anti-N monoclonal antibody-coupled immunoaffinity chromatography or phenyl sepharose hydrophobic interaction chromatography.

• Journal of Microbiology and Biotechnology
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• v.7 no.6
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• pp.386-390
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• 1997

A xylanase from the Bacillus sp. strain DSNC 101, isolated from soil, was purified to homogeneity by anion-exchange and hydrophobic interaction chromatography followed by gel filtration chromatography. The enzyme cleaved xylan, but not carboxymethyl cellulose, Avicel, soluble starch, and pNPX. The main product of oat spelts xylan hydrolysates was xylobiose. The xylanase had a molecular weight of 25 kDa determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Optimum temperature and pH for the xylanase activity were $50^{\circ}C$ and 6.0, respectively. $K_{m}\;and\;V_{max}$ of the enzyme for oat spelts xylan were 12.5 mg of xylan/ml and 869.5 unit/mg of protein, respectively. Xylanase was completely inhibited by Hg, Cu, and N-bromosuccinimide, but was stimulated by Ca, Co, and Mg.

• Journal of the Korean Applied Science and Technology
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• v.15 no.1
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• pp.99-108
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• 1998

Novel type surfactants containing two long-chain hydrophobic alkyl groups and two hydrophilic sulfonate groups were successfully synthesized by reactions of ethylene glycol diglycidyl ether with long-chain fatty alcohols, after then by reactions with 1,3-propane sultone and sodium hydride under THF solvent. All these compounds, so called Gemini surfactants, were purified by thin layer chromatography and column chromatography. Their structures were identified by FT-IR and $^{1}H$-NMR.

• Bulletin of the Korean Chemical Society
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• v.10 no.6
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• pp.491-495
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• 1989

Resolution of enantiomers of DNS-amino acids has been achieved by a reversed phase liquid chromatography with an addition of a copper(Ⅱ) complex of N-benzyl-L-hydroxyproline to the mobile phase. N-Benzyl-L-hydroxyproline was prepared and used as a chiral ligand of copper(Ⅱ) chelate for the optical resolution. The pH and the concentration of copper(Ⅱ) chelate, organic solvent, and buffer agent in the mobile phase all affect the optical resolutions of dansyl amino acids. The elution orders between D and L-DNS-amino acids were different depending on the structure of the side chain of the amino acids. The retention mechanism for the chiral separation of the dansyl amino acids can be illustrated by the equilibrium of ligand exchange and by hydrophobic interaction with $C_{18}$ stationary phase. The chiral separation can be illustrated with cis and trans effect of the ligand exchange reaction.

• Bulletin of the Korean Chemical Society
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• v.13 no.3
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• pp.280-285
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• 1992

Enantiomeric separation of free amino acids has been achieved by a reversed phase liquid chromatography with addition of a Cu(Ⅱ) complex of N-alkyl-L-proline (alkyl: propyl, pentyl or octyl) to the mobile phase. The amino acids eluted were detected by a postcolumn OPA system. N-alkyl-L-proline was prepared and used as a chiral ligand of Cu(Ⅱ) chelate for the enantiomeric separation. The concentration of the Cu(Ⅱ) chelate, the organic modifier and pH affect the enantiomeric separation of free amino acids. The retention behaviour, varied with change in pH and the concentration of the Cu(Ⅱ) chelate, was different compared with those of the derivatized amino acids. The elution orders between D- and L-forms were consistent except histidine showing that L-forms elute earlier than D-forms. The retention mechanism for the enantiomeric separation can be illustrated by the stereospecificity of the ligand exchange reaction and the hydrophobic interaction between the substituent of amino acids and reversed phase, $C_18$.

• Bulletin of the Korean Chemical Society
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• v.9 no.6
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• pp.341-345
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• 1988

Separation of optical isomers of dansyl amino acids by a reversed phase liquid chromatography has been accomplished by adding a copper (II) chelate of N-benzyl-L-proline to the mobile phase. The pH, the eluent composition and the concentration of copper (II) chelate all affect the optical separations. The elution orders between D and L DNS-amino acids were consistant except dansyl phenylalanine showing that D forms of DNS-amino acids elute earlier than L forms. These behaviors are different from the results obtained by the use of copper (II) proline. The retention mechanism for the optical separation of the dansyl amino acids can be explained by the equilibrium of liqand exchange and by hydrophobic interaction.

• Journal of Microbiology and Biotechnology
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• v.25 no.5
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• pp.704-708
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• 2015

For the analysis of multiple-reaction intermediates for long-chain dicarboxylic acid biotransformation, simple and reproducible methods of extraction and derivatization were developed on the basis of gas chromatography with flame ionization detector (GC-FID) instead of mass spectrometry. In the derivatization step, change of the ratio of pyridine to MSTFA from 1:3 to 9:1 resulted in higher peak intensity (p = 0.021) and reproducibility (0.6%CV) when analyzing 32 g/l ricinoleic acid (RA). Extraction of RA and ω-hydroxyundec-9-enoic acid with water containing 100 mM Tween 80 showed 90.4-99.9% relative extraction efficiency and 2-7%CV compared with those with hydrophobic ethyl acetate. In conclusion, reduction of the pyridine content and change of the extraction solvent to water with Tween 80 provided compatible derivatization and extraction methods to GC-FID-based analysis of longchain carboxylic acids.