• Journal of the Korean Wood Science and Technology
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• 제35권5호
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• pp.100-108
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• 2007

$\beta$-Glucosidase from Laetiporus sulphureus among the enzymes related to lignocellulosic biomass degradation to sugars for using alternative bioethanol production was characterized. The highest activity of $\beta$-glucosidase was obtained on cellobiose at shaking culture. For the characterization and purification of $\beta$-glucosidase culture solution was concentrated and then purified by FPLC using ion exchange and size exclusion column. According to the results of SDS-PAGE, native PAGE and microfluidic system of purified enzyme, protein band was observed at about 132 kDa. Optimal pH and temperature of purified $\beta$-glucosi-dase were 5.0 and $60^{\circ}C$, respectively. In the kinetic properties of $\beta$-glucosidase on various substrates such as sophorose, gentiobiose and cellobiose, $K_m$ was 0.81, 1.07 and 1.70 mM, respectively.

• 생명과학회지
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• 제6권4호
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• pp.250-263
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• 1996

In this study Carotenoprotein from Styela clava were extracted, and purified by ammonium sulfate fraction, Sephadex G- 200 gel chromatography and DEAE-cellulose ion exchange chromarography. The purified carotenoprotein from styela clava had absorption maxima of 487nm, 463nm and 280nm, and the carotenoid liberated from carotenoprotein had 478nm and 452nm with inflexion. One miligram of caroteno-protein contained 0.35 $\mu$g of carotenoid. The carotenoprotein had an approximate molecular weight of 398 kDa (gel filtration). SDS-PAGE showed only a single polypeptide chain with a molecular weight of 62.4 kDa. The amino acid composition of the carotenoprotein were mainly glutamic acid(11.48%), valine(10.75%), leucine (10.45%), aspartic acid(9.94%), while cysteine and tryptophan were not found. The carotenoprotein contained lipid as structure units. In the carotenoprotein, the major fatty acids were oleic acid, plamitoleic acid and palmiunsaturated fatty acids 33.6%, saturated fatty acids 18.6%. In addition, the levels of higher unsaturated fatty acids were high as much as 30.8% of the total fatty acids. Carotenoid was extracted from the carotenoprotein by acetone. Thin layer chromatography showed only carotenoid to be present. Its chemical reactivities and spectroscopic properties were studied and elucidated as astaxanthin.

• 한국미생물·생명공학회지
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• 제23권4호
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• pp.454-460
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• 1995

Acetylxylan esterase II was produced by Escherichia coli HB101 harboring the recombinant plasmid pKMG7 which contained the estII gene of Bacillus stearothermophilus. Optimal medium for the production of the acetylxylan esterase by E. coli HB101/pKMG7 was determined to contain 0.5% galactose, 1% yeast extract and 1% NaCl. The enzyme produced was purified to homogeneity using a combination of 20-50% ammonium sulfate precipitation, DEAE-Sepharose CL-6B chromatography and Sephacryl S-200 gel filtration. The temperature and pH optimum of the esterase were 45$\circ$C and pH 6, respectively. The essential amino acids for the esterase activity were found to be methionine, serine, and cysteine. Molecular weight of the esterase was determined to be 28 kDa by SDS-polyacrylamide gel electrophoresis, and 120 kDa by gel filtration. This suggests that the functional enzyme is a homomeric tetramer. The esterase had an isoelectric point of pH 3.4. The N-terminal amino acid sequence of the enzyme was Ala-Leu-Phe-Glu-Ser-Arg-Phe-Phe-Ser-Glu-Val-Leu-Gly-Leu.

• 한국미생물·생명공학회지
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• 제19권6호
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• pp.592-597
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• 1991

토양 분리균인 B.stearothermophilus가 생산하는 xylanase를 ammonium sulfate 분획, DEAE-Sepharose CL-6B ion exchange chromatography, Sephadex G-100 gel 여과 및 열처리 등의 과정을 거쳐 단일 단배질로 분리 정제하였다. 170,000의 분자량을 본 정제 xylanase는 pH8과 pH10 사이의 넓은 최적 pH를 보였으며 $55^{\circ}C$에서 최대 활성을 나타내었다. $55^{\circ}C$에서 2시간의 열처리에 의해서도 활서의 손실이 거의 없을 정도로 열에 매우 안정하였으며 $co^{2+}$와 $Mn^{2+}$에 의해서 현저한 활성화 효과를 보였다.

• 생명과학회지
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• 제5권4호
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• pp.170-180
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• 1995

A carotennnoprotein from the skin of Ascidian(Halocynthia roretzi) was extracted by Triton X-100 and purified by ammonium sulfate fraction, SephadexG-200 charomatography and DEAE-cellulose ion exchange chromatography. The carotenoprotein was redwith broad $\lambda$$_{max}$ between 495, 467 and 318nm. The red carotenoprotein had an approximate molecular weight of 326KDa(gel filtration). SDS-PAGE indicated the presence of two polypeptodes of 84.1KDa and 74.4KDa, with different mobility in polyacrylamide gel electrophoresis. In the presence of denaturing agents such as organic solvent aand extreme pH, the red complex readily disociates to liberate the yellow carotenoid($\lambda$$_{max}$ 452nm) and a colourless apoprotein. The amino acid composition of carotenoprotein were mainly threonine(15.2%), aspartic acid(12.2%), glutamic acid(11.9%) and serine(9.6%), while proline was not found. The carotenoprotein consisted of lipids as structure units. Its major fatty acids composion were C$_{18:1}$, C$_{16:1}$, and C$_{16:0}$. The monounsaturated fatty acids(41.5%) contained abundant content compared to other fatty aacids(polyunsaturated fatty acids 37.4%, saturated fatty acids 20.6%).

• Journal of Microbiology and Biotechnology
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• 제20권12호
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• pp.1681-1688
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• 2010

A screening for cellobiohydrolase (CBH) activity was performed and Fomitopsis pinicola KMJ812 was selected for further characterization as it produced a high level of CBH activity. An extracellular CBH was purified to homogeneity by sequential chromatography of F. pinicola culture supernatants. The molecular mass of the F. pinicola CBH was determined to be 64 kDa by SDS-PAGE and by size-exclusion chromatography, indicating that the enzyme is a monomer. The F. pinicola CBH showed a $t_{1/2}$ value of 42 h at $70^{\circ}C$ and catalytic efficiency of $15.8mM^{-1}s^{-1}(k_{cat}/K_m)$ for p-nitrophenyl-${\beta}$-D-cellobioside, one of the highest levels seen for CBH-producing microorganisms. Its internal amino acid sequences showed a significant homology with hydrolases from glycoside hydrolase family 7. Although CBHs have been purified and characterized from other sources, the F. pinicola CBH is distinguished from other CBHs by its high catalytic efficiency and thermostability.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1997년도 춘계학술대회
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• pp.93-93
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• 1997

Analysis of protein is often frustrated by the inability to isolate large amounts of purified protein from a native source. To overcome this problem, fusion protein expression systems such as pGEX system have been widely used. Using pGEX system, the desired protein could be easily obtained in a large amount in E. coli, and then the fusion protein could be used for the study of the function of the given protein. To analyze and purify the GST fusion protein, anti-GST antibody could be used as one of the system of choice. However, the production and characterization of monoclonal anti-GST antibody has not been studied extensively yet. To produce monoclonal anti-GST antibody, GST was purified from E. coli transformed with pGEX-cs, one of the pGEX system and was used as an antigen. The monoclonal antibody was produced by fusion of the immunized spleen cells with SP2-0 myeloma cells. The antibody was characterized by ELISA, western blotting, etc. The monoclonal antibody produced in this study (mAb-GSTA) showed strong and specific immunoreactivity against not only GST but also GST-fusion proteins. Also, mAb-GSTA was successfully used for the immunoaffinity purification of the GST ${\beta}$-Rc.-third intracellular-loop fusion protein. The results of the present study suggest that mAb-GSTA may be used for the identification and purification of GST fusion proteins.

• Bulletin of the Korean Chemical Society
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• 제32권12호
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• pp.4253-4257
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• 2011

Sodium dodecyl sulfate-capillary gel electrophoresis (SDS-CGE) and capillary isoelectric focusing (CIEF) were employed to characterize and compare ricin E purified from the small grain seeds of Ricinus communis with ricin D isoform. During the purification of ricin E using ion-exchange and size-exclusion chromatography, SDS-CGE was found to be useful for monitoring the efficiencies of purification steps. SDS-CGE showed that the molecular size of ricin E was not significantly different from that of ricin D, which was confirmed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. CIEF was useful for discriminating ricin E from ricin D based on their isoelectric points (pI). The pI values of ricin E and D were 8.6-8.8 and 7.0-7.4, respectively. This study demonstrates the usefulness of SDS-CGE and CIEF for the characterization of ricin toxins.

• KSBB Journal
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• 제14권3호
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• pp.322-327
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• 1999

토양에서 분리된 Streptomyces sp으로부터 cholesterol oxidase의 정제 및 효소학적 특성을 조사하였다. 본 효소의 정제는 50~80% 포화의 황산암모늄 침전 및 cholesterol affinity column chromatography를 통하여 28.3%의 수율로 정제 되었다. 정제된 효소는 SDS-PAGE에서 단일한 밴드를 보였으며 분저량은 약 60,000 dalton으로 추정되었으며, HPLC분석 결과 단일의 peak로 검출되었다. 본 효소의 특성을 검토한 결과, 금속 이온으로 Hg와 Cu의 존재시 크게 저해를 받았고, dithiothreitol 과 mercaptoethanol과 같은 저해제에 의해서 상당히 실활되었다. 본 cholesterol oxidase의 Michaelis 상수는 cholesterol을 기질로하여 Lineweaver-Burk plot분석에서 1.38mM로 추산되었다. 정제효소의 아미노산 조정은 약 416개의 잔기로 추정되며 glycine, alanine, threonine의 함량이 높은 반면, methionine, isoleucine의 함량은 극히 낮았다.

• BMB Reports
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• 제29권5호
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• pp.455-461
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• 1996

A serine proteinase was purified from Acanthamoeba culbertsoni by 41~80% ammonium sulfate fractionation, ion exchange chromatography, affinity chromatography and gel filtration chromatography. The molecular weight of the purified enzyme was estimated to be 108.0 kDa by gel filtration chromatography and 54.0 kDa by SDS-PAGE. Therefore, the purified enzyme seemed to be a dimer. Isoelectric point was 4.5. The enzyme activity was highly inhibited by the serine proteinase inhibitors diisopropyl fluorophosphate (OFP) and phenylmethyl sulfonylfluoride (PMSF). It had a narrow pH optimum of 6.5~7.5 with a maximum at pH 7.0. These data suggested that the purified enzyme was a neutral serine proteinase. Optimal temperature was $37^{\circ}C$. It was stable for at least 16 h at $4^{\circ}C$ and $37^{\circ}C$, but it was rapidly inactivated at $65^{\circ}C$ The activity of the purified enzyme was not influenced significantly by $Mg^{2+}$, $Mn^{2+}$, $Zn^{2+}$ or $Ca^{2+}$. However, the enzyme activity was highly inhibited by $Hg^{2+}$ The enzyme degraded type I collagen and fibronectin, but not BSA, hemoglobin, lysozyme, immunoglobulin A or immunoglobulin G.