• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.366-366
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• 2005

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.186-186
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• 2005

• 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.

• Applied Biological Chemistry
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• v.38 no.2
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• pp.106-110
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• 1995

An alkaline protease-producing bacterium was isolated from Korean hot pepper paste and identified as Alteromonas sp. CN301. A alkaline protease was purified and characterized. The optimal pH and temperature for the enzyme activity were pH 12.0 and $35^{\circ}C$, respectively. Molecular weight of the enzyme was determined as 31,000 dalton by the SDS-PAGE. The enzyme was stable in the range of $pH\;6.0{\sim}13.0$ showing the residual activity above 80% of the enzyme activity. The residual activity of the enzyme was 64% when the enzyme was incubated at $50^{\circ}C$ for 1 hr. The activity of the enzyme was not affected by most metal ions tested except $Hg^{2+}$, and activated by Triton X-100, Tween 20 and Tween 80. The enzyme activity was severely inhibited by PMSF and EDTA, suggesting that the enzyme is serine protease having metal ion in its structure.

• Journal of Applied Biological Chemistry
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• v.44 no.2
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• pp.98-99
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• 2001

• Journal of Applied Biological Chemistry
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• v.51 no.3
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• pp.95-101
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• 2008

The gene encoding a putative esterase of Xanthomonas oryzae pv. oryzae was cloned using PCR technique. The gene was expressed with His6 tag in E. coli. One-step purification of the recombinant esterase with Ni-NTA resin resulted in one band by SDS-PAGE analysis. The purified enzyme showed a molecular weight of 30 kDa, as expected, therefore the enzyme was a mononer. The enzyme was the most active toward p-nitrophenyl (p-NP) acetate and p-NP-butyrate to a lesser extent. However, the enzyme could not hydrolyze p-NP-myristate, palmitate, and stearate. Therefore, the enzyme is considered as an esterase, very different from lipase. The purified esterase had optimal pH at around 8.0 and was stable in a broad range of pH values. The optimal temperature ranged from 30 to $40^{\circ}C$, and the residual activity observed after heat treatment at $55^{\circ}C$ for 20 min was 72 % of the initial activity. The activity was inhibited by the presence of copper and cobalt ions.

• Applied Biological Chemistry
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• v.36 no.1
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• pp.45-50
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• 1993

A psychrotrophic microorganism isolated from Alaska pollack (Theragra chalcoramma) produced soymilk-clotting enzyme(s) with relatively low proteolytic activity. The isolate No. 268 was tentatively identified as Pseudomonas sp. Soymilk-clotting activity of the crude enzyme solution was observed at temperatures ranging from 20 to $60^{\circ}C$ and the optimum temperature was $40^{\circ}C$. When the crude enzyme solution was preincubated for 30 minutes, the clotting activity was stable at temperatures up to $30^{\circ}C$ and 75% of the activity was retained at $40^{\circ}C$. The clotting activity was decreased as the pH of soymilk was increased from 5.8 to 7.3.

• Journal of Microbiology and Biotechnology
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• v.17 no.6
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• pp.1002-1009
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• 2007

A rapid, convenient homogeneous competitive enzyme immunoassay for estimating the amount of fenthion is described. The assay utilizes glucose-6-phosphate dehydrogenase-hapten conjugates that are inhibited in solution by antibodies obtained from bovine serum albumin-hapten conjugates. In order to investigate the effects of bridging group recognition on the sensitivity of dose response characteristics, the bridging groups of varying alkyl chain length were attached at the phosphate position of fenthion. Among the antibodies used, the one obtained from the use of hapten (fenthion analog) with the same bridging group structure that was used in preparing the enzyme-fenthion conjugates showed maximum inhibition (up to 51.8%) in the absence of fenthion. In the presence of fenthion, the activity of the enzyme-hapten conjugate is regained in an amount proportional to the fenthion concentration. Under the optimized condition, the $ED_{50}$ value for fenthion was $0.809{\mu}g/ml$. The assay developed in this study is a rapid effective screening method for fenthion prior to precise analysis.

• Journal of Applied Biological Chemistry
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• v.50 no.4
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• pp.196-201
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• 2007

An intracellular invertase was purified to homogeneity from the cell extract of an alkalophilic and thermophilic Bacillus sp. TA-11, which was classified as a new species belonging to Bacillus cereus based on chemotaxanomic and phylogenetic analyses. The purified enzyme with a recovery of 26.6% was determined to be a monomeric protein with a molecular weight of 23 kDa by SDS-PAGE and 26 kDa by gel filtration. The maximum enzyme activity was observed at pH 7.0 and $50^{\circ}C$, and the purified enzyme was stable at the pH range of 5.0 to 8.0 and below $60^{\circ}C$. $K_m$ and $V_{max}$ values of the enzyme for sucrose were 370 mM and 3.0 ${\mu}M$ per min, respectively. The enzyme activity was significantly inhibited by bivalent metal ions ($Hg^{2+}$, $Cd^{2+}$ and $Cu^{2+}$) and sugars (glucose and fructose).

• Journal of Applied Biological Chemistry
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• v.43 no.3
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• pp.147-151
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• 2000

A gene, nprM, from Bacillus megaterium ATCC 14945 was obtained by PCR using primers synthesized based on two nprM sequences from two different strains, and cloned into Escherichia coli. The gene nprM encoded an extracellular neutral protease, and the molecular mass of the expressed enzyme was estimated to be approximately 36kDa on a denaturating gel. The enzyme was activated by $Ca^{2+}$, and the optimum concentration of $Ca^{2+}$ was 5 mM. The enzyme was inhibited by EDTA but not by PMSF. The optimal pH and temperature of the cloned enzyme were $50^{\circ}C and pH 7.5-8.0, respectively, and were similar to those of the enzyme from the gene gonor cell. The cloned NprM caused internal cleavage of the native endoglucanase of B. subtilis BSE616 as a model foregin protein, and resulted in a small truncated but still active endoglucanase.