• 한국식품과학회지
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• 제25권1호
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• pp.39-45
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• 1993

대두 단백분해효소(pepsin, actinidin)를 작용시켜 단백질 분자에 변형을 줌으로써 이에 따른 식품학적인 기능성의 변화에 대하여 연구하였다. 효소와의 반응시간에 따른 변화에 대하여 연구하였다. 효소와의 반응시간에 따른 대두단백질의 가수분해도를 측정한 결과, pepsin은 초기부터 매우 급격히 대두단백을 가수분해 시켰으며 반면 actinidin에 의한 가수분해는 반응시간이 경과함에 따라 완만하게 진행되었다. PAGE에 의한 결과는 두 효소가 비슷한 경향을 보여 반응이 진행될수록 아랫쪽으로 점차 이동하는 하나의 넓은 band를 보였다. SDS-PAGE에 서는 native SPI가 약 9개의 뚜렷한 band를 보였으나 actinidin에 의한 경우 $3{\sim}4$개의 band를 나타내었다. 그러나 pepsin으로 5분 반응시킨 경우 MW $24,000{\sim}13,000$에 이르는 하나의 band를 나타내어 actinidin이 특정한 band를 선택적으로 가수분해하는 경향과는 다른 결과를 보였다. 대두 단백 가수분해물의 기능적 특성을 측정한 결과, pepsin으로 반응시킨 경우 용해도는 대조군이나 actinidin의 경우보다 뚜렷이 증가했고, 전 pH 범위에서 유화형성력이 향상되었다. 또한 모든 실험군의 기포형성력이 전 pH에서 증가했으며, 등전점 부근에서는 효소반응 시간이 경과할수록 기포안정성도 증가하였다. 그러나 actinidin 처리시 등전점 부근에서만 유화형성력이 향상되었고, 5분 반응시킨 실험군의 기포형성력이 가장 높았으며, alkaline 범위에서 기포안정성이 증가되었다. 이와 같이 각 가수분해물의 기능성의 차이는 단백분해효소마다 그 작용부위가 다르고 이에 따른 단백 가수분해물의 물리, 화학적 특성이 달라져, 그 결가 가수분해물의 기능적 특성에 영향을 끼치는 것으로 사료된다.

• 한국식품과학회지
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• 제40권3호
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• pp.290-296
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• 2008

찹쌀 전분을 가교화 후 4가지 상업용 ${\alpha}$-amylase 효소와 반응시켜 CLE 찹쌀 전분을 제조하고 이들의 이화학적 특성을 연구하였다. CLE 찹쌀 전분의 팽윤력 및 용해도는 천연 찹쌀 전분에 비해 다소 증가되는 경향을 보였다. 등온흡습곡선에서는 CLE 처리에 따른 수분 감소현상을 보였으나 유의적인 차이는 없었다. RVA특성을 검토한 결과 Termamyl과 Liquozyme으로 처리한 찹쌀 전분은 전반적으로 효소에 의한 가수분해가 강하게 진행되어 온도에 따른 점도의 변화가 크게 나타나지 않았으며, Fungamyl과 Kleistase로 처리한 찹쌀 전분은 효소에 의한 가수분해가 상대적으로 미약하게 진행되어 가교화에 의한 특성을 더 많이 나타내었다. DSC 열적 특성의 경우 호화개시온도, 호화종결온도 그리고 호화온도범위, 호화 엔탈피 모두 각 전분간에 유의적인 차이가 나타나지 않았다. X-ray 회절 분석 결과 또한 CLE 찹쌀 전분과 천연 찹쌀 전분 모두 A형의 결정 형태를 나타내었고, 상대적 결정화도의 차이가 나타나지 않는 것으로 보아 가교화 및 가교화후 효소처리가 찹쌀 전분의 결정형영역에는 영향을 주지 않는 것으로 보여진다.

• Journal of Microbiology and Biotechnology
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• 제22권12호
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• pp.1636-1643
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• 2012

Enzymatic pre-bleaching by modification of pulp fibers with xylanases is an attractive approach to reduce the consumption of toxic bleaching chemicals in the paper industry. In this study, an alkaliphilic endoxylanase gene was isolated from metagenomic DNA of a structurally stable thermophilic lignocellulose-degrading microbial consortium using amplification with conserved glycosyl hydrolase family 10 primers and subsequent genome walking. The full-length xylanase showed 78% sequence identity to an endo-${\beta}$-1,4-xylanase of Clostridium phytofermentans and was expressed in a mature form with an N-terminal His6 tag fusion in Escherichia coli. The recombinant xylanase Xyn3F was thermotolerant and alkaliphilic, working optimally at $65-70^{\circ}C$ with an optimal pH at 9-10 and retaining >80% activity at pH 9, $60^{\circ}C$ for 1 h. Xyn3F showed a $V_{max}$ of 2,327 IU/mg and $K_m$ of 3.5 mg/ml on birchwood xylan. Pre-bleaching of industrial eucalyptus pulp with no prior pH adjustment (pH 9) using Xyn3F at 50 IU/g dried pulp led to 4.5-5.1% increase in final pulp brightness and 90.4-102.4% increase in whiteness after a single-step hypochlorite bleaching over the untreated pulp, which allowed at least 20% decrease in hypochlorite consumption to achieve the same final bleaching indices. The alkaliphilic xylanase is promising for application in an environmentally friendly bleaching step of kraft and soda pulps with no requirement for pH adjustment, leading to improved economic feasibility of the process.

• Food Science and Biotechnology
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• 제17권5호
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• pp.1092-1096
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• 2008

Commercial food products from major cities of Coahuila, Mexico were screened to identify residues of transgenic deoxyribonucleic acid (DNA) and/or proteins. After performed, an inventory on all products that contained a soybean-based ingredient in a commercial grocery store in the city of Saltillo, Coahuila, Mexico, 245 food products were identified and grouped in 15 classes according to the soybean ingredient as well as the manufacturing process used for their elaboration. Similar sampling was made for the different food classes in the cities of Monclova, Piedras Negras, and Torreon. A total of 88 samples were analyzed and DNA was extracted by the hexadecyltrimethyl-ammonium bromide (CTAB) technique with slight modification to obtain better DNA quality (1). In addition, segments of the transgenic genes one that codifies for 5-enolpyruvylshikimate-3-phosphate synthase (epsps), cry 1A, and the cauliflower mosaic virus (CaMV) promoter were amplified using polymerase chain reaction (PCR). The transgenic proteins 5-enolpyruvylshikimate-3-phosphate synthase (CP4 EPSPS) and insecticidal crystal protein (Cry 1Ab/Ac) were identified using double antibody sandwich-enzymatic linked immunoassay analysis (DAS-ELISA). Presence of transgenic genes and/or proteins was identified in 35.3% of the commercial products samples.

• Preventive Nutrition and Food Science
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• 제15권1호
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• pp.57-66
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• 2010

Passion fruit fiber pectin gels represent a new alternative pectin source with potential for food and non-food applications on a commercial scale. Pectic polysaccharides were extracted from passion fruit (Passiflora edulis) fiber using citric acid as a clean catalyst and autoclaved for 20 to 60 min at $121^{\circ}C$. The best condition of pectin yield with the highest molecular weight was obtained with 1.0% of citric acid (250 mg/g dry passion fruit fiber pectin) for 20 min of autoclaving. Spectroscopic analyses by Fourier transform infrared, enzymatic degradation reactions, and ion-exchange chromatography assays showed that passion fruit pectin extracted for 20 min was homogeneous high methoxylated pectin (70%). Gel permeation analysis confirmed that the pectin extract obtained by autoclaving by 20 min showed higher molecular weights than those autoclaved for 40 and 60 min. Passion fruit pectin extracted for 20 min was enzymatically modified with fungal pectinmethylesterase to create restructured gels. Short autoclave treatment (20 min) with citric acid as extractant resulted in a significant increase of gel strength, improving pectin extraction in terms of functionality. The treatment of solubilized material (pectic polysaccharides) in the presence of insoluble material (cellulose and hemicellulose) with pectinmethylesterase and calcium led to the creation of a stiffer passion fruit fiber pectin gel, while syneresis was not observed.

• Applied Biological Chemistry
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• 제30권3호
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• pp.234-241
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• 1987

어육(魚肉) 단백질(蛋白質)의 기능성(機能性)을 개선(改善)하기 위해 정어리 분말단백질(粉末蛋白質)의 pepsin 가수분해물(加水分解物)을 이용(利用)하여 plastein을 합성(合成)하기 위한 반응조건(反應條件)을 검토(檢討)하였다. Plastein의 합성조건(合成條件)은 papain 및 pepsin의 경우 pH는 각각(各各) 6, 4, 기질농도(基質濃度)는 각각(各各) 50%, 40%, 반응시간(反應時間) 및 효소농도(酵素濃度)는 각각(各各) 2시간(時間), 1%였으며 반응온도(反應溫度)는 papain 및 pepsin 모두 $50^{\circ}C$였다. 기질(基質)의 가수분해도(加水分解度)가 60% 이상(以上)에서 plastein 합성반응(合成反應)이 이루어졌으며 가수분해도(加水分解度)가 77.2% 이상(以上)이었을 때 plastein 생성량(生成量)이 높았다. 단백질(蛋白質) 함량(含量)은 50% ethanol 침전(沈澱) plastein이 90% 정도(程度)로 10% TCA 침전(沈澱) plastein의 74%에 비(比)해 높았으나 회분(灰分) 함량(含量)은 10% TCA 침전(沈澱) plastein이 14.4%로 50% ethanol 침전(沈澱) plastein의 1.2%보다 월등히 높았다. 수율(收率)은 papain의 경우 10% TCA 침전(沈澱) plastein 및 50% ethanol 침전(沈澱) plastein이 각각(各各) 49.5%, 43.6%로서 pepsin plastein의 45.3%, 41.0%보다 약간 높았다.

• Journal of Microbiology and Biotechnology
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• 제28권9호
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• pp.1482-1492
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• 2018

Fusarium oxysporum trypsin (FOT) is a fungal serine protease similar to mammal trypsin. The FOT could be successfully expressed in Pichiapastoris by engineering the natural propeptide APQEIPN. In this study, we constructed two recombinant enzymes with engineered amino acid sequences added to the N-terminus of FOT and expressed in P. pastoris. The N-terminal residues had various effects on the structural and functional properties of trypsin. The FOT, and the recombinants TE (with peptide YVEF) and TS (with peptide YV) displayed the same optimum temperature ($40^{\circ}C$) and pH (8.0). However, the combinants TE and TS showed significantly increased thermal stability at $40^{\circ}C$ and $50^{\circ}C$. Moreover, the combinants TE and TS also showed enhanced tolerance of alkaline pH conditions. Compared with those of wild-type FOT, the intramolecular hydrogen bonds and the cation ${\pi}$-interactions of the recombinants TE and TS were significantly increased. The recombinants TE and TS also had significantly increased catalytic efficiencies (referring to the specificity constant, $k_{cat}/K_m$), 1.75-fold and 1.23-fold than wild-type FOT. In silico modeling analysis uncovered that the introduction of the peptides YVEF and YV resulted in shorter distances between the substrate binding pocket (D174, G198, and G208) and catalytic triad (His42, Asp102, and Ser180), which would improve the electron transfer rate and catalytic efficiency. In addition, N-terminal residues modification described here may be a useful approach for improving the catalytic efficiencies and characteristics of other target enzymes.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2012년도 정기총회 및 춘계학술발표회
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• pp.8-8
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• 2012

Ginseng have been traditionally used for strengthening immunity, providing nutrition and recovering health from fatigue. Recently, pharmaceutical activities of ginseng roots have been proven by many researches, and ginseng has become a world-famous medicinal plant. Ginseng saponin, ginsenoside, is one of the most important secondary metabolite in ginseng which has various pharmacological activities. Many studies have aimed to convert major ginsenosides to the more active minor ginsenoside Rg3 for consumer demand ginseng product. Microbial strain GS514 strain was isolated from soil around ginseng roots for enzymatic preparation of ginsenoside Rg3, which strain shows strong ability of converting ginsenoside Rb1and Rd into Rg3 in the solution with NaCl. The gene encoding a ${\beta}$-glucosidase from this GS514 was cloned and expressed in the BL21 (DE3) strain of Escherichia coli. The recombinant enzyme was purified and characterized. The molecular mass of purified was 87.5 kDa, as determined by SDS-PAGE. The gene sequence revealed significant homology to the family 3 glycoside hydrolases. The purified single enzyme also catalyzed the conversion of ginsenoside Rb1 into Rg3. This target enzyme will be able to produce as much saponin for consumer demand ginseng product. Anti-apoptotic proteins bind with pro-apoptotic proteins to induce apoptosis mechanism. Over expression of these anti-apoptotic proteins lead to several cancers by preventing apoptosis. Docking simulations were performed for anti-apoptotic proteins with several ginsenosides from Panax ginseng. Our finding shows ginsenosides particularly Rg3, Rh2 and Rf have more binding affinity with apoptotic proteins. Further, these docking system of each ginsenosides can be extended to experimental screen system for further brief confirmations of several diseases.

• 한국식품과학회지
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• 제33권6호
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• pp.769-773
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• 2001

두유에서 발생되는 비지와 대두의 일반성분과 단백질의 추출률을 비교하기 위해 시간, 온도, pH별로 분석하였고, 단백질 분자들 사이의 상호작용에 관여하는 물질 urea, SDS, 2-mercaptoethanol를 사용하여 비지단백질의 insolubilization mechamism을 조사하였다. 또한 enzyme modification으로 기능성을 향상시켜 식품소재로서의 이용 가능성에 대해 분석하였다. 비지와 대두는 각각 37.3%, 42.5%의 단백질을 함유하고 있으며 비지는 생산공정 증의 과도한 열처리에 의하여 극히 낮은 용해도를 나타냈다. 비지단백질의 낮은 용해도는 주로 disulfide bonding에 의한 cross linking에 기인하는 것으로 밝혀졌다. 비지단백질과 대두단백질은 pH 3, pH 4에서 가장 낮은 용해도를 보였다. Carbohydrase와 protease를 첨가하여 단백질의 추출츌을 비교한 결과는 비지와 대두는 carbohydrase에서 미세한 반응을 보여 단백질의 용해도에 큰 영향을 주지 못하였으나 여러 protease 가운데 Alcalase는 비지단백질의 용해도를 급격히 증가시켰다.

• Environmental Engineering Research
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• 제24권4호
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• pp.670-679
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• 2019

Lignin complexity molecule makes its biodegradation difficult during lignocellulosic wastes composting. So, the improvement of its biodegradation has usually been considered as an objective. This study aimed to determine the impact of Trametes trogii inoculation on organic matter and particularly on lignin and cellulose during green wastes co-composting with olive mill waste water sludge and coffee grounds. Three types of heaps (H1, H2 and H3) were investigated during 180 d. H3 and H2 were inoculated at the beginning of the process (t₀) and 120 d later (t₁₂₀), respectively while H1 was the control. Results showed the absence of pH stabilization in H3 during the first month. Also, in this period we observed a faster degradation of some easily available organic matter in H3 than in the other heaps. After 120 d, a better cellulose decomposition (25.28%) was noticed in H3 than in H1 and H2 (16%). Inoculation during the second fermentation phase induced supplementary lignin degradation in H2 with a percentage of 35% against 23 and 26% for H1 and H3, respectively. For all the runs, a Fourier Transform Infrared analysis showed aliphatic groups' decrease, OH groups' increase and lignin structural modification.