• 한국미생물·생명공학회지
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• 제11권1호
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• pp.47-52
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• 1983

Aspergillus sp.C-58 균주가 생산하는 extracellular inulase에 대하여 pH, charcoal처리 및 ammonium sulfate로 분별염석한 후 DEAE- cellulose를 이용한 column chromatography에 의하여 3개의 효소단백질(Peak I, II, III)로 분획되었으며 그 비율은 31. 1 : 1.7 : 1이였다. P- I, II의 I/S는 그 비율이 0.23 및 0.24로 거의 동일하였으나 P-III는 1.1로 P-I및 P-II와 상이하였다. Peak I 효소에 대하여 DEAE-Sephadex A-50을 이용한 ion exchange chromatography에 의하여 추출효소에 비교하여 약 408배 정제되었으며 다시 Sephadex G-75 및 Sephadex G-100에 2회 gel filtration하여 약 482배 정제되었다. 이상과 같이 정제한 Peak I의 효소액은 poly acrylamide를 이용한 disc gel electrophoresis 및 ultra centrifugation에 의하여 단일 단백질로 확인되었다.

• 한국식품과학회지
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• 제16권4호
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• pp.392-397
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• 1984

Rhiz. oryzae가 생산(生産) 정제효소(精製酵素) glucoamylase I (G I) 과 glucoamylase II (G II) 의 gel filtration에 의(依)하여 추정(推定)된 분자량(分子量)은 120,000, 127,000이었다. glucoamylase I 과 II 의 등전점(等電点)은 각각(各各) pH 7.25. pH 7.75 이었고 반응(反應) 최적온도(最適溫度)는 다같이 $50^{\circ}C$, 안정온도범위(安定溫度範圍) 는 다같이 pH5.0부근(附近)이었으며 안정(安定)pH범위(範圍)는 각각(各各) $pH3.5{\sim}8.0$, $pH4.5{\sim}8.0$이었다. 가용성전분(可溶性澱粉)에 대(對)한 Michaelis 상수는 glucoamylase I 이 4.545mg/ml, glucoamylase II 가 5.560mg/ml이었다. glucoamylase I 은 $Hg^{++}$, $Pb^{++}$, p-CMB, IAA에 의하여, glucoamylase II는 $Hg^{++}$, $Mn^{++}$, p-CMB, IAA에 의하여 저해(沮害)되었다.

• Journal of Microbiology
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• 제37권1호
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• pp.21-26
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• 1999

Two novel calcium-binding proteins, named CAB-I and CAB-II, have been isolated from Streptomyces coelicolor. Purification of the calcium-binding proteins involved heat treatment, fractionation with ammonium sulfate, acid treatment, anion exchange and hydrophobic interaction column chromatography, FPLC gel filtration, and preparative isoelectric focusing. A chelex competitive assay and 45Ca autoradiography verified the calcium-binding ability of the proteins. The major band CAB-II has an apparent molecular weight of 26,000 determined by SDS-polyacrylamide gel electrophoresis and 340,000 determined by gel filtration. The isoelectric point of this molecule showed the acidic nature of the molecule. N-terminal amino acid sequence analysis shows homology to rat Ca2+/calmodulin-dependent protein kinase-II (CAB-II) and yeast phosphoprotein phosphatase (CAB-I).

• 미생물학회지
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• 제32권4호
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• pp.297-300
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• 1994

토양에서 분리한 방선균에서 제한효소 활성을 조사하여 그 가운데 Streptomyces diastatochromogenes로부터 제한효소 활성을 확인하였다. 이 균주의 제한효소 SdiI을 균체 15g으로부터 streptomycin sulfate침전, ammonium sulfate 침전, hydroxylapatite colume chromatography, Sephacryl S-200 HR column chromatography, hydroxylapatite column chromatography의 단계를 거쳐 분리하였고, SDS-polyacrylamide gel-electrophoresis에 의하면 소단위체 분자량은 약 35,000Da으로 추정되었다.

• 한국식품과학회지
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• 제16권3호
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• pp.322-328
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• 1984

Pizopus oryzae가 생산(生産)하는 glucoamylase를 유안(硫安)및 acetone 분획(分劃)과 이온교환수지의 column chromatography에 의하여 정제(精製)하였다. 즉(卽) 조효소액(粗酵素液)을 유안분획(硫安分劃) acetone 분획(分劃), DEAE-cellulose column chromatography, CM-cellulose column chromatography에 의(依)하여 두가지형(型)의 glucoamylase를 분리정제(分離精製)하였으며 이들을 각각(各各) glucoamylase I과 II라고 하였다. Glucoamylase I과 II의 Specific activity는 각각(各各) 157.6U/mg protein (조효소액(粗酵素液)의 37.5배(倍)) 164.7U/mg protein (조효소액(粗酵素液)의 39.2배(倍)) 이었고 수율(收率)은 각각(各各) 4.3%, 3.8%이었다. Glucoamylase I과 II는 polyacrylamide disc gel electrophoresis와 SDS-polyacrylamide gel electrophoresis에 의(依)하여 각각(各各) 단일(單一)한 band를 나타내었고 이 단백질(蛋白質) band는 옥도염색(沃度染色)에 의(依)해 glucoamylase 활성(活性)을, PAS염색(染色)에 의(依)해 glycoprotein임을 확인(確認)하였다.

• 한국미생물·생명공학회지
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• 제14권6호
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• pp.447-453
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• 1986

고온, 알칼리성 Bacillus K17이 생성하는 extracellular xylanase를 각종 resin으로 정제하여 비흡착 분획에서 xylanase I과 흡착 분획에서 xylanase II를 분리정제하였고, SDS-Polyacrylamide gel electrophoresis에 의하여 분자량을 측정하였던바 xylanase I은 23,000, xylanase II는 47,000으로 추정되었다. Xylanase I 및 II는 최적온도, 최적 pH, 열 안정성, pH 안정성, 기질 친화력에서 차이가 있었으며 Cu$^{++}$, Ag$^+$, Fe$^{++}$, Hg$^{++}$에 의해 다같이 저해되었다. Xylanase I은 xylan을 Xylobiose, xylotriose, xylotetraose로 분해시키며 그 분해율이 22%로 나타났다. 그리고 xylanase II xylose, xylobiose, xylotriose로 분해시키며 그 분해율이 30%이었다. 효소적 분석은 효소가 갖는 기질특이성으로 인해 다성분계의 분석재료로부터 측정한 성분만을 정량 가능하므로 생체성분의 분석에 널리 활용되고 있다.

• Journal of Microbiology and Biotechnology
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• 제15권2호
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• pp.239-246
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• 2005

Some characteristics of two forms of glucoamylase (glucan 1 A-$\alpha$-glucosidase, EC 3. 2. I. 3) purified from Aspergillus coreanus NR 15-1 were investigated. The enzymes were produced on a solid, uncooked wheat bran medium of A. coreanus NR 15-1 isolated from traditional Korean Nuruk. Two forms of glucoamylase, GA-I and GA-II, were purified to homogenity after 5.8-fold and 9.6-fold purification, respectively, judged by disc- and SDS-polyacrylamide gel electrophoresis. The molecular mass of GA-I and GA-II were estimated to be 62 kDa and 90 kDa by Sephadex G-1OO gel filtration, and 64 kDa and 91 kDa by SDS-polyacrylarnide gel electrophoresis, respectively. The optimum temperatures of GA-I and GA-II were 60$^circ$C and 65$^circ$C, respectively, and the optimum pH was 4.0. The activation energy (Ea value) of GA-I and GA-II was 11.66 kcal/mol and 12.09 kcal/mol, respectively, and the apparent Michaelis constants (K_{m}) of GA-I and GA-II for soluble starch were found to be 3.57 mg/ml and 6.25 mg/ml, respectively. Both enzymes were activated by 1 mM Mn^{2+} and Cu^{2+}, but were completely inhibited by 1 mM N­bromosuccinimide. The GA-II was weakly inhibited by 1 mM p-CMB, dithiothreitol, EDTA, and pyridoxal 5-phosphate, but GA-I was not inhibited by those compounds. Both enzymes had significant ability to digest raw wheat starch and raw rice starch, and hydrolysis rates of raw wheat starch by GA-I and GA-II were 7.8- and 7.3-fold higher than with soluble starch, respectively.

• Korea-Australia Rheology Journal
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• 제11권4호
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• pp.275-278
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• 1999

Soft polymeric materials have gained importance in recent years, namely in food, pharmaceuticals, photographic media, adhesives, vibration dampeners and superabsorbers (to name a few), but also as inter-mediates for selforganization of molecules or supramolecules into long range order. Many of these soft materials are close to their gel point, i.e. they are liquids just before reaching their gel point or they are solids which have barely passed the gel point. New rheological methods need to be developed for the understanding of these soft materials; the typical liquid properties (viscosity) and typical solid properties (modulus) are not applicable since they diverge at the gel point. This will be discussed in the following. Fortunately, chemical gelation experiments with model polymers has given insight into the behavior at the gel point (Winter and Mours, 1997). This knowledge of the critical gel provides us with a reference state when working with soft polymeric materials. Chemical gels will serve as model materials for the exploration of physical gels. A novel method for detecting the gel point has been proposed: the instant of liquid-to-solid transition(gel point) is marked by the crossover of the normalized dynamic moduli G'/cos($n_c$$\pi$/2) and G"/sin($n_c$$\pi$/2).>/2).

• Corrosion Science and Technology
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• 제17권1호
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• pp.30-36
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• 2018

The high rate of corrosion of magnesium alloys makes it limited for industrial applications. Therefore, surface treatment is required to enhance their corrosion resistance. In our study, a chemical conversion coating for protecting the corrosion of the magnesium alloy, AZ31B, was prepared by using a phosphate-permanganate solution. The chemical conversion coating had a limited protection ability due to defects arising from cracks and pores in the coating layer. The sol-gel coating was prepared by using trimethoxymethylsilane (MTMS) and 3-glycidoxypropyltrimethoxysilane (GPTMS) as precursors, and aluminum acetyl acetonate as a ring opening agent. The corrosion protection properties of sol-gel and conversion coatings in 0.35wt% NaCl solution were measured by the electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization test. The EIS results indicated that the resistance of the chemical conversion coating with the sol-gel coating was significantly improved through the sol-gel sealed phosphate-permanganate conversion coating. The results of the potentiodynamic polarization test revealed that the sol-gel coating decreased the corrosion current density ($I_{corr}$). The SEM image showed that the sol-gel coating sealed conversion coating and improved corrosion protection.

• 한국세라믹학회지
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• 제32권1호
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• pp.17-24
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• 1995

The TEA complex polymeric sol was prepared by the alkoxide sol-gel method. The purpsoe of this experiment was to vefity the particle shape in the sol from the investigation of the rheological properties. TEA retarded hydrolysis rate by the reaction with alkoxide enough to make a stable transparent sol in the wide range of composition. From the results of the viscosity change with time, the optimum mole ratio for spinning was selected as 0.5 mole of TEA, 3 mole of H2O and the optimum viscosity was 104 cPs. The rheological behavior of the sol showed that the particle shape in the sol was linear, which was adequate for fiber drawing.