• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.360-365
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• 1996

To investigate the presence of brassinosteroids in rice bran and pㅐlished rice, they were extracted with MeOH. The extracts were purified through sequential procedure of solvent fractionation, silica gel adsorption chromatography, Sephadex LH-20 column chromatography and charcoal adsorption chromatography. The activity of brassinosteroids was monitored by the rice inclination test and its presence was confirmed in each purification step. The purified active components were further separated by TLC and HPLC. Brassinosteroids in active fractions of rice bran were identified as castasterone and teasterone by HPLC. We acknowledge that our work is probably the first report of brassinosteroids in mature seeds of rice The more amount of brassinosteroids was confirmed in rice bran than polished rice. The contents of castasterone and teasterone which were identified in rice bran were 0.15 ng/g and 0.37 ng/g, respectively.

• Korean Journal of Medicinal Crop Science
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• v.12 no.3
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• pp.179-182
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• 2004

Bioassay-directed fractionation of the dried roots of Salvia miltiorrhiza led to the isolation of abietane tanshinones, cryptotanshinone and dibydrotanshinone I. Their structures were elucidated using $^1H-\;and\;^{13}C-NMR$, UV, IR and mass spectral analyses. These compounds exhibited a moderate antimicrobial activities against Staphylococcus epidemidis, Staphylococcus aureus, and Staphylococcus pyogene.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.4
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• pp.903-906
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• 2008

Woodfordia fruticosa Kurz (Lythraceae) is used in the treatment of various ailments in traditional medicines. DPPH activity guided fractionation and purification process was used to identify the free radical-scavenging components from the flowers of this plant. The methanolic extract of the plant was first fractionated into four extracts; namely, n-hexane, chloroform, ethyl acetate and water fractions. Among them, the ethyl acetate fraction was found to be the most effective and was further subjected to activity guided-fractionation and isolation procedures. After successive column chromatography on silica gel and Sephadex LH-20, gallic acid, which is responsible for the radical scavenging activity, was isolated and its structure was elucidated by spectral methods ($^1H$ NMR, $^{13}C$ NMR) and by comparison with literature.

• Applied Biological Chemistry
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• v.45 no.4
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• pp.190-194
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• 2002

Expression of Bacillus subtilis glutamyl-tRNA synthetase (GluRS) in Escherichia coli is lethal for the host, probably because this enzyme misaminoacylates ${tRNA_l}^{Gln}$ with glutamate in vivo. In order to overexpress B. subtilis GluRS, encoded by the gltX gene, in E. coli, this gene was amplified from B. subtilis 168 chromosomal DNA using PCR method and the entire coding region was cloned into a pET11a expression vector so that it was expressed under the control or the T7 Promoter. The resulting recombinant pEBER plasmid was transformed into E. coli Novablue (DE3) bearing the T7 RNA polymerase gene for expression. After IPTG treatment, the overproduced enzyme was purified using ammonium sulfate fractionation, Source Q anion exchange chromatography, Superdex-200 gel filtration, and Mono Q anion exchange chromatography. The purified enzyme yielded 18-fold increase in specific activity over the crude cell extract and its molecular weight was approximately 55 kDa on SDS-PAGE.

• Food Science and Preservation
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• v.14 no.3
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• pp.332-335
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• 2007

Hot water and 95%(v/v) ethanol extracts were prepared from dried Lespedeza cuneata seeds and antioxidant compounds were isolated by solvent fractionation, silica gel adslorption chromatography, Sephadex LH-20 column chromatography, and preparative HPLC. Antioxidant activity was measured using DPPH radical scavenging activity. The 80%(v/v)ethanol and ethylacetate fraction of Lespedeza cuneata seed extracts had stronger antioxidant effects than did the n-hexane fraction. The active antioxidant compounds obtained from hot water and 95%(v/v) ethanol extracts may be identical, based on analysis by Sephadex LH-20 column chromatography and preparative HPLC.

• Korean Journal of Microbiology
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• v.35 no.4
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• pp.315-321
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• 1999

This study has been performed to deveope a yeast strain having high ${\alpha}$-amylase production ability using nuclear transfer method. Hybrids formed between the strains of Saccharomyces fiburigera KCTC 7393 and Saccharomyces cerevisiae KCTC 7049 (tyr-, ura-)were obtained by nuclear transfer technique. Nuclei isolated from the wild type S. fiburigera strain were transfered into auxotrophic mutants S. cerevisiae and selected the hybrids showing an increased starch degrading capability were selected (MN-16). This transformant grew best and produced maximal ${\alpha}$-amylase activity on the medium containing 2% (V/V) soluble starch. ${\alpha}$-Amylase from MN-16 was purified electrophoretically homogenety and its properties were investigated. The enzyme was purified about 10.6 fold with an overall yield 9.7% from the culture medium by ammonium sulfate fractionation. DEAE-Sephacel column chromatography, and Sephacryl S-200 column chromatography. The purified enzyme showed a single band on SDS-polyacrylamide gel electrophoresis. The molecular weight of the ${\alpha}$-amylase was estimated to be 53,000 daltons by SDS-PAGE and by gel permeation chromatography on Sephacryl S-200. The purified enzyme showed the maximum activity at pH 5.5 and 40${\circ}C$. The km value for soluble starch was 2.5㎎/㎖. The enzyme activity increased in the presence of $Ca^{2+}, Co^{2+}, EDTA, Mg^{2+}, Mn^{2+}, Zn^{2+}$, but inhibited by $Cu^{2+}, Fe^{2+}$, and $Ni^{2+}$

• Korean Journal of Food Science and Technology
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• v.28 no.3
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• pp.604-608
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• 1996

The antimicrobial activty of leek (Allium tuberosum) was investigated against 17 strains of microorganisms. Methanol extracts of leek showed the growth inhibition effects on the wide range of microorganisms including gram positive bacteria, gram negative bacteria and yeasts. The extracts were analysed by using solvent fractionation, silica gel adsorption chromatography, Sephadex LH-20 column chromatography, TLC, silica gel partition chromatography and HPLC techniques. Six components whose molecular weights range from 200 to 400 were confirmed to have the antimicrobial activity.

• Korean Journal of Microbiology
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• v.30 no.3
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• pp.160-163
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• 1992

Killer toxin from killer yeast fusant FWKS 260 developed by protoplast fusion between the wild killer yeast and alcohol-fermenting yeast was purified by ammonium sulfate fractionation. Amicon PM I0 concentration. Sephadex G-200 and Scphadcx G-75 column chromatography. The purified killer toxin showed a single band by SIX-polyacvlamide gel electrophoresis. The protein part of killer toxin was active site. which was found by treating the proteolytic enzyme such as pronase E and pepsin to killer toxin. The killer toxin was stable at pH 2.0-5.0 and 20$^{\circ}$C. but inactivated with increasing temperature. The molecular weight was determined to be approximately 13.000 according to the results obtained from the SDS-polyacrylamide gel electrophoresis. It was confirmed that the purified killer toxin is glycoprotein by showing a red single band after st'tining with Schiffs reagent.

• Korean Journal of Food Science and Technology
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• v.21 no.4
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• pp.569-574
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• 1989

These studies were conducted to investigate the purification and characterization of Kiwifruit protease, and the results obtained were as follows The protease was purified by ammonium sulfate fractionation, Sephadex G-100 filtration and DEAE-Sephadex A-50 column chromatography and purified enzyme gave a single protein band on polyacrylamide gel electrophoresis The specific activity of purified enzyme was 30,10 units/mg protein and the yield was 7.48. The purified enzyme showed a high affinity for casein and hemoglobin. The optimal pH and temperature for enzyme activity were 7.0 and $45^{\circ}C$, respectively. The enzyme activity was strongly inhibited by $HgCl_2,\;MnSO_4$. However. the enzyme was activated by cysteine and EDTA. The Michaelis constant for casein was calculated to be 50.5mg/ml according to the Line weaver-Burk method, and its molecular weight was determied as 23,500 by polyacrylamide gel electrophoresis.

• Applied Biological Chemistry
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• v.38 no.6
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• pp.534-540
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• 1995

Alkalophilic coryneform bacteria TU-19 isolated from soil extracellularly produced at least three proteases (Protease I, II, and III). Investigating the cultural conditions related to the enzyme production of this bacterial cell, the optimum pH and temperature were 10.0 and $30^{\circ}C$, respectively. In order to purify these enzymes from the 2 day culture broth ammonium sulfate fractionation, gel filtration and QAE-Sephadex column chromatography were performed step by step. And then these three proteases were purified to near homogeneity by judging from SDS-PAGE pattern, and had the molecular weights of 120, 80, and 45 kilodaltons, respectively. The optimum pH and temperature for the enzyme activity of Protease I and II were 10.5 and $45^{\circ}C$, respectively, and Protease II were 11.0 and $50^{\circ}C$. And the enzymes were completely inhibited by PMSF suggesting serine protease, but not affected by pCMB. 1,10-phenanthroline, IAA, and EDTA.