• Microbiology and Biotechnology Letters
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• v.26 no.5
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• pp.427-434
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• 1998

An alkaline protease was 4-fold purified, yielding 2.3% of recovery by ammonium sulfate precipitation, CM-cellulose column chromatography and Sephadex G-100 column chromatography. The purified enzyme was estimated to be monomeric with molecular weight of about 62,000 from polyacrylamide gel eletrophoresis (PAGE) and sodiumdodecylsulfate polyacrylamide gel electrophoresis (SDS-FAGE). The optimal pH and temperature of the alkaline pretense activity were 11.0 and 50$^{\circ}C$, respectively, exhibiting high stability at pH value from 6.0 to 11.0 at 50$^{\circ}C$ for 30 minute. The alkaline pretense was activated by MnSO$_4$, CaCl$_2$, and was inhibited by CuSO$_4$, ZnSO$_4$, HgCl$_2$, EDTA and EGTA. Also, the enzyme was found to be a metaloenzyme requiring Mn$\^$2+/ as cofactor. The NH$_2$-terminal amino acid of alkaline protease was alanine. The Km and Vmax values of this enzyme for casein was 4.0 mg/$m\ell$ and 5,500 unit/$m\ell$, respectively.

• The Korean Journal of Mycology
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• v.13 no.2
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• pp.89-97
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• 1985

To find antibacterial strains of the soil microorganisms in Korea, they were isolated from the soil samples of different locations and screened for antibacterial activity against several standard microorganisms. An isolate among them had antibacterial activities against gram-positive and gram-negative bacteria. The examination of its morphological, biochemical, cultural and physiological characteristics according to the International Streptomyces Project methods showed that it belongs to the genus Streptomyces. This strain appears to be a novel strain when it was compared with those species of the genus which have been so far reported. The antibiotic metabolite was produced in the submerged culture of the strain. This metabolite was extracted from the culture filtrate and purified by ion-exchange column chromatography. Physico-chemical properties of the antibacterial metabolite were characterized.

• Korean journal of food and cookery science
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• v.11 no.5
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• pp.542-547
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• 1995

Pectinesterase was isolated from the culture medium of Aspergillus japonicus and partially purified by DEAE-Sephadex batchwise, Sephadex G-75 gel filtration and ion exchange chromatography. The purified enzyme solution was completely free from polygalacturonase which depolymerizes pectin molecule. The ability of the pectinesterase to demethylate high methoxyl pectin was investigated. On 20 minute of incubation methoxyl content of low methoxyl pectin decreased from 88％ to 6.93%. In general gel prepared with the pectin containing lower methoxyl content showed the lower value of percent sag, and showed the hieher Bel strength. Textural characteristics of pectin gel determined by Rheometer showed that as the methoxyl content was lowered, hardness and resilience of the gel were increased and cohesiveness was decreased. Apple juice containing HMP and organic acids can be converted into low methoxyl pectin apple jelly by the action of pectinesterase and addition of calcium ion. The strength of low methoxyl pectin apple jelly increased when it stored at room temperature.

• Nuclear Engineering and Technology
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• v.12 no.2
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• pp.99-105
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• 1980

The distribution of $^{55}$ Mn and $^{38}$ Cl recoil species following radiative neutron capture in permanganates, chlorates and perchlorates has been investigated by using ion-exchange chromatography method. The whole of the $^{55}$ Mn radioactivity in permanganates appeared in two valence states, the $^{38}$ Cl radioactivity in chlorates in two valence states and also the $^{38}$ Cl radioactivity in perchlorates in three valence states. Recoil energy was calculated. The internal conversion of $^{38}$ Cl isomer transition affects the retention value. The greater the radii of the cation, the higher is the probability of the recoil atom breaking through the secondary cage. In ammonium salt, the ammonium ion behaves as a reducing agent. Crystal structures with their greater free space have shown low retention.

• Journal of Microbiology and Biotechnology
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• v.24 no.10
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• pp.1337-1345
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• 2014

A novel antifungal protein produced by the fungal strain Penicillium citrinum W1, which was isolated from a Southwest Indian Ocean sediment sample, was purified and characterized. The culture supernatant of P. citrinum W1 inhibited the mycelial growth of some plant pathogenic fungi. After saturation of P. citrinum W1 culture supernatants with ammonium sulfate and ion-exchange chromatography, an antifungal protein (PcPAF) was purified. The N-terminal amino acid sequence analysis showed that PcPAF might be an unknown antifungal protein. PcPAF displayed antifungal activity against Trichoderma viride, Fusarium oxysporum, Paecilomyces variotii, and Alternaria longipes at minimum inhibitory concentrations of 1.52, 6.08, 3.04, and $6.08{\mu}g/disc$, respectively. PcPAF possessed high thermostability and had a certain extent of protease and metal ion resistance. The results suggested that PcPAF may represent a novel antifungal protein with potential application in controlling plant pathogenic fungal infection.

• Journal of Microbiology and Biotechnology
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• v.8 no.3
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• pp.270-276
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• 1998

Extracellular ${\alpha}$-glucosidase was purified to homogeneity from moderately thermophilic Bacillus sp. DG0303. The thermostable ${\alpha}$-glucosidase was purified by ammonium sulfate fractionation, ion-exchange chromatography, preparative polyacrylamide gel electrophoresis (PAGE), and electroelution. The molecular weight of the enzyme was estimated to be 60 kDa by SDS-PAGE. The optimum temperature for the action of the enzyme was at $60^{\circ}C$. It had a half-life of 35 min at $60^{\circ}C$. The enzyme was stable at the pH range of 4.5~7.0 and had an optimum pH at 5.0. The enzyme preparation did not require any metal ion for activity. The thermostable ${\alpha}$-glucosidase hydrolyzed the ${\alpha}$-1,6-linkages in isomaltose, isomaltotriose, and panose, and had little or no activity with maltooligosaccharides and other polysaccharides. The $K_m$ (mM) for p-nitrophenyl-${\alpha}$-D-glucopyranoside (pNPG), panose, isomaltose, and isomaltotriose were 4.6, 4.7, 40.8, and 3.7 and the $V_{max}$(${\mu}mol{\cdot}min^-1$$mg^-1$) for those substrates were 5629, 1669, 3410, and 1827, respectively. The N-terminal amino acid sequence of the enzyme was MERVWWKKAV. Based on its substrate specificity and catalytic properties, the enzyme has been assigned to be an oligo-1,6-glucosidase.

• BMB Reports
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• v.31 no.2
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• pp.130-134
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• 1998

An aldolase gene has been cloned from Methanococcus jannaschii. The coding region of the gene has been expressed in E. coli using a pET system to a level of 30% of total cellular proteins. The protein was purified to more than 95 % homogeneity by heat treatment and ion exchange chromatography. The protein performed an aldol condensation reaction with glyceraldehyde as substrate and dihydroxyacetone phosphate as a carboxyl donor. The protein was determined to be a type II aldolase which requires the $Zn^{2+}$ ion as a metal cofactor. This enzyme has a broad range of optimum pH (7-9) and temperature ($50-80^{\circ}C$). It shows strong stability against heat, chemical denaturants, as well as a high percentage' of organic solvents. The half-life of this enzyme at $85^{\circ}C$ is more than 24 h and it maintains more than 90% of aldolase activity in the presence of 6 M urea, 50% acetonitrile, or 15% isopropyl alcohol.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.4
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• pp.570-577
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• 1995

Aspergillus sp. SB-2704 was selected for its strong polygalacturonase activity among various strain of mold found in soil. It was found that production of polygalacturonase reached to maximum when the wheat bran medium containing 1% polypepton, 1% glucose, and 0.2% FeSO4 were cultured for 3 days at 35$^{\circ}C$. Polygalacturonase was purified 20.90 fold from Aspergillus SB-2704. The purification procedures include ammonium sulfate treatment, gel filtration on Sephdex G-150 and DEAE-cellulose ion exchange chromatography. Yield of the enzyme purification was 4.34%. Purified enzyme was confirmed as a single band by the polyacrylamide gel electrophoresis. When the purified enzyme was applied to SDS-polyacrylamide gel electrophoresis, the molecular weight was estimated to be 36,000. The optimum pH for the enzyme activity was 5.5 and optimum temperature was 5$0^{\circ}C$. The enzyme is stable in acidic condition. The activity of purified enzyme was inhibited by Pb2+, Hg2+ and Ba2+, whereas activated by Cu2+, Mn2+, Mg2+ and Fe2+. The activity of polygalacturonase was inhibited by the treament wit maleic anhydride, iodine, and EDTA. The result indicate the possible involvement of histidine and metal ion at active site.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.840-845
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• 2011

Degradation products of agarose are biologically active and thus used as an ingredient in pharmaceuticals or functional cosmetics. Furthermore, it has been strongly considered as a substrate for bio-ethanol fermentation. Recently, we isolated new agarase-producing microorganism, Pseudoalteromonas sp. from south sea of Korea. In this study, we aimed to separate and purify the agarase from culture broth of this strain. Separation of agarase was performed by ion- exchange chromatography on DEAE-Sepharose resin. Equilibrium pH and volume ratio of resin to the amount of protein were optimized for the efficient adsorption of protein. 410 ${\mu}g$ of protein was completely adsorbed to 3 mL of resin at pH 7.5. The total amount of eluted protein increased as NaCl concentration increased to 400 mM at isocratic elution. Agarase was separated by linear gradient elution of NaCl (0~1,000 mM). Three major protein peaks were observed and the presence or absence of agarase in these eluted proteins was measured by Lugol's staining technique. Only six eluted protein fractions showed strong agarase activity.

• Microbiology and Biotechnology Letters
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• v.17 no.1
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• pp.35-45
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• 1989

Streptococcus thermophilus 510 was investigated as n potential source of $\beta$-galactosidase. Optimum cultural conditions for maximum enzyme production were 0.5% loctose as carbon source, initial pH 7.0, 37 $^{\circ}C$, and 18 hours of cultivation. The enzyme was purified to homogeneity by ammonium sulfate fractionation, protamine sulfate precipitation, Sephadex G-200 gel filtration, and DEAE-Sephadex A-50 ion exchange chromntography. The purified enzyme exhibited an optimum pH at 1.0, and an optimum temperature of 5$0^{\circ}C$. Metal ions such as Mn$^{2+}$ and $K^+$, dithiothreitol, and 2-mercaptoethanol stimulated $\beta$-galactosidase activity. Ethylenediamine tetraacetic add, 8-hydroxyquinoline, Hg$^2+$, Zn$^{2+}$, Co$^{2+}$, $Ca^{2+}$, and galactose were inhibitory. The $K_m$ and V$_{max}$ for o-nitrophenyl $\beta$-D-galactopyranoside were 1.25mM and 88.50$\mu$moles/min.mg protein, respectively. The molecular weight was estimated to be 520,000, and the amino acid composition indicated relatively high contents of glutamic acid, aspartic acid, leucine, and valine.