• 한국균학회지
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• 제31권2호
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• pp.77-83
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• 2003

천연자원인 cellulose를 이용하기 위하여 섬유소분해효소의 생산성이 강한 Roseofomes subflexibilis의 배양학적 특성을 조사한 결과는 다음과 같다. 1.섬유소분해효소의 생산 및 균사체 생장에 적합한 탄소원은 glucose인 것으로 나타났으며, 균사체배양의 탄소원은 saccharose로 최적농도는 1.2%였다. 2. 균사체배양의 유기질소원은 yeast extract이었으며. 최적농도는 1.5%이었다. 또한 무기질소원은 $NH_{4}H_{2}PO_{4}$를 잘 이용하는 것으로 나타났고, 최적농도는 1.1% 첨가시 균사체의 생장이 좋았다. 3. 균사체배양의 아미노산의 영향을 조사한 결과 aspartic acid가 가장 좋았으며, 최적농도는 0.1%이었다. cysteine 첨가시 효소생산과 균사체의 생장 모두에서 효과적이었다. 4.무기염류의 영향은 $Al_{2}(SO_{4})_{3}$ 첨가시 효과적이었으며 최적농도는 0.1 M이었다. 5.배양온도는 $30{\circ}C$였으며, 최적 pH는 4.0인 것으로 나타났다.

• Journal of Microbiology and Biotechnology
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• 제9권1호
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• pp.62-69
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• 1999

In order to investigate the critical amino acid residues involved in the catalytic activities of $\beta$-cyclodextrin glucanotransferase ($\beta$-CGTase) excreted by Bacillus firmus var. alkalophilus, the amino acid residues in $\beta$-CGTase were modified by various site-specific amino acid modifying reagents. The cyclizing and amylolytic activities of $\beta$-CGTase were all seriously reduced after treatment with Woodward's reagent K (WRK) modifying aspartic/glutamic acid, N-bromosuccinimde (NBS) modifying tryptophan, and diethylpyrocarbonate (DEPC) modifying histidine residues. The roles of tryptophan and histidine residues in $\beta$-CGTase were further investigated by measuring the protection effect of various substrates during chemical modification, comparing protein mobility in native and affinity polyacrylamide gel electrophoresis containing soluble starch, and comparing the $K_m$ and $V_{max}$ values of native and modified enzymes. Tryptophan residues were identified as affecting substrate-binding ability rather than influencing catalytic activities. On the other hand, histidine residues influenced catalytic ability rather than substrate-binding ability, plus histidine modification had an effect on shifting the optimum pH and pH stability.

• Preventive Nutrition and Food Science
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• 제6권1호
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• pp.79-81
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• 2001

Deoxynucleoside kinases exist as heterodimeric pairs specific for deoxyadenosine/deoxyguanosine kinase (dAK/dGK) and deoxyadenosine/deoxycytidine kinase (dAK/dCK). The aspartic acid-84 in dGK was mutated to alanine, asparagine and glutamic acid by site-directed mutagenesis. The mutation resulted in a drastic decease in dGK activity compared to the unmodified cloned enzyme while it increased production of dAK activity. The mutated dak/dgk genes, which synthesize tandem deoxyadenosine/deoxyguanosine kinase, were inserted back to the Lactobacillus acidophilus and Lactococcus lactis by electroporation to determine the effect of site-directed mutation of he enzymes on the microbial growth. However, no significant change was observed in cell growth and lactic acid production between wild type and mutant lactic acid bacteria.

• 한국환경농학회지
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• 제24권3호
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• pp.245-252
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• 2005

The objective of the present work was to determine the corresponding uptake and assimilation of ${NO_3}^-$ in roots and shoots of leafy radish by applying of mixed amino acids (MAA). The amino acids used in this experiment were alanine (Ala), ${\beta}-alanine\;({\beta}-Ala)$, aspartic acid (Asp), asparagines (Asn), glutamic acid (Glu), glutamine (Gln), and glycine (Gly). Leafy radish was grown by conventional fertilization with macro- and micronutrients under controlled conditions. The 15-day-old seedlings were treated 0, 0.3 and 3.0 mM of MAA containing 5 mM ${NO_3}^-$ in growth medium. Nitrate uptake was determined by following ${NO_3}^-$ depletion from the uptake solution. The activity of the enzymes related to the process of ${NO_3}^-$ reduction (NR: nitrate reductase; NiR: nitrite reductase; GS: glutamine synthetase) and the content of ${NO_2}^-\;and\;{ND_3}^-$ were analyzed in shoots and roots. The results of this study showed that ${NO_3}^-$ uptake was inhibited 38% with treatment of 0.3 mM of MAA. However, there was more than three times increase of N03- uptake in 3.0 mM MAA. In addition, the enzymatic activities were positively affected by the high MAA rate. Finally, the ${NO_3}^-$ content was increased slightly both in shoots and roots of leafy radish by MAA treatments.

• 한국식품영양과학회지
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• 제36권8호
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• pp.1022-1030
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• 2007

붉은 대게 가공부산물로 이용도가 낮은 자숙액을 이용하여 효소 가수분해물의 제조를 시도하였고, 아울러 이의 맛, 영양 및 건강기능에 대한 특성을 조사하였다. 붉은 대게 자숙액은 일반성분 및 안전성면에서 식품가공소재로 이용하여도 아무런 문제가 없었다. 1단 가수분해물의 경우 TCA soluble index(TSI), ACE 저해능 및 항산화능을 고려하는 경우 Alcalase로 2.0시간 반응시켜 제조하는 것이 가장 적절하였다. 붉은 대게 자숙액 유래 Alcalase 1단 가수분해물을 기질로 하여 Flavourzyme, Neutrase 및 Protamex로 각각 2시간씩 연속적으로 가수분해시킨 2단 가수분해물의 ACE 저해능 및 항산화능은 1단 가수분해물에 비하여 유사하거나 약간 우수하여 2단 가수분해의 필요성이 인정되지 않았다. 붉은 대게 자숙액에 비하여 이를 Alcalase 처리한 가수분해물의 경우 일반성분 및 색조는 차이가 없었으나, glutamic acid 및 aspartic acid와 같은 맛에 관여하는 유리아미노산의 경우 증가하였다. 붉은 대게 유래 Alcalase 처리 가수분해물의 아미노산 함량은 11,859.6 mg/100 mL이었고, 주요 아미노산으로는 glutamic acid(10.2%), proline(10.1%) 및 glycine (10.7%) 등이었다.

• 한국식품과학회지
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• 제26권1호
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• pp.44-50
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• 1994

미역 추출액의 효과적인 추출조건을 선정하기 위하여 5가지 추출 방법인 $Na_{2}EDTA$-끓임(방법 A). HCI-끓임(방법 B), $HCI-Na_{2}EDTA$-끓임(방법 C), $Celluclast-Na_{2}EDTA-HCI$-끓임(방법 D), $Ultrazyme-Na_{2}EDTA-HCI$-끓임(방법 E)을 비교하였다. 그 결과는 방법 D가 고형분 수율 63.14%와 단백질 수율 26.39%로 가장 높았다. 맛과 관계가 있는 아미노태 질소의 회수량은 870 ppm의 아미노태 질소농도를 보인 방법 C가 가장 높았고 방법 D(770 ppm), 방법 B(570 ppm), 방법 A(480 ppm), 대조구(270 ppm) 순으로 나타났다. 추출액의 정미 성분은 주로 alanine, aspartic acid, glutamic acid이었으며 미역 추출액의 유리 아미노산 총량은 방법 A(8.88 mg%), D(4.14 mg%), E(4.18 mg%)순으로 증가하였고 대조구(1.71 mg%)보다 $2.5{\sim}5.1$배 높았다. 미역 추출액의 관능적 성질 비교는 특히 Celluclast 처리한 방법 D가 유의적으로 적은 비린 냄새와 높은 해조류맛을 나타내었다. 따라서 방법 D를 가장 효과적인 방법임이 밝혀졌다.

• KSBB Journal
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• 제6권4호
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• pp.327-336
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• 1991

수산물 가공시 부산물로 얻어지는 어피(魚皮)를 보다 효율적으로 이용하기 위하여 효소로 대구피를 가수분해할 때 가수분해조건을 구명하였으며 그 가수분해물을 이용한 천연조미료(모조간장 및 복합조미료)의 개발을 시도하였다. pH-drop법으로 대구피분해에 있어서의 collagenase, trypsin 및 pronase의 활성을 비교해 본 결과 pronase가 가장 활성이 높았으며 이 pronase의 $K_m$ 및 $V_{max}$값은 각각 1.82 mgN/ml, 0.06 mgN/mL/min였다. Pronase에 의한 대구피 가수분해조건은 반응온도 $50^{\circ}C$, 반응시간 3시간, pH6, 효소농도 0.03%였으며, 이 조건하에서의 가수분해도는 78.8%였다. 그러나 대구피를 collagenase로 1시간 분해시킨 후 pronase로 처리할 경우 가수분해도는 90.83%였다. 이때 가수분해물의 분자량은 8,000 dalton이었다. 아미노산 조성은 glycine(27.95%), glutamic acid(10.94%), proline(10.48%), aspartic acid(7.47%), serine(7.39%)이 전체 아미노산의 64.23%였으나 쓴맛을 내는 valine, methionine, isoleucine, leucine, phenylalanine, histidine 등은 13.05%에 불과하였다. 가수분해물과 기타 부원료로 제조한 모조간장원액과 시판 100% 양조간장을 8:2(v/v)로 혼합한 모조간장은 시판대두간장에 비해 최소유의차 검정 결과 맛, 색 및 종합평가면에서 5% 유의수준내에서 유의차가 없었다. 가수분해물 31.7% 함유한 복합조미료도 시판 복합조미료와 관능적으로 비교해 본 결과 복합조미료로서의 손색이 없는 제품이었다.

• 한국수산과학회지
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• 제46권1호
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• pp.37-45
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• 2013

This study was conducted to improve the yield of extracts from Alaska pollock Theragra chalcogramma head and sea tangle Laminaria japonica byproducts using various commercial enzymes, such as Alcalase, Flavourzyme, Neutrase (NH), and Protamex. Among the enzymatic hydrolysates, the yield was highest in hydrolysate incubated with NH for 4 h. NH-treated hydrolysates (NHH) also improved functional properties, such as angiotensin-I converting enzyme (ACE) inhibitory activity and 2,2-diphenyl-1-picryldrazyl (DPPH) radical scavenging activity, as compared to extracts from Alaska pollock head and sea tangle byproducts. Total free amino acid and taste values of NHH were 379.7 mg/100 mL and 24.03, respectively, after digestion for 4 h. These values are 2.2-fold and 1.9-fold higher compared with those of water soluble fractions extracted from Alaska pollock head and non-forming sea tangle, respectively. According to the taste value results, the major taste-active compounds among free amino acids of NHH were glutamic acid and aspartic acid. These results suggest that NHH can be used as an ingredient for natural seasoning preparation.

• Journal of Applied Biological Chemistry
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• 제56권2호
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• pp.89-93
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• 2013

Gamma-aminobutyric acid (GABA) aminotransferase (gabT) and succinic semialdehyde dehydrogenase (gabD) genes from Pseudomonas fluorescens KCCM 12537 were cloned into a single pETDuet-1 vector and co-expressed in Escherichia coli BL21(DE3) simultaneously. The mixture of both enzymes, called GABase, is the key enzyme for the enzymatic analysis of GABA. The molecular mass of the GABA aminotransferase and succinic semialdehyde dehydrogenase were determined to be 52.8 and 46.7 kDa following computations performed with the pI/Mw program, respectively. The GABase activity between pH 6.0 and 9.0 for 24 h at $4^{\circ}C$ remained over 75%, but under pH 6.0 decreased rapidly. The GABase activity between 25 and $35^{\circ}C$ by the treatment at pH 8.6 for 30 min remained over 80%, but over $35^{\circ}C$ decreased rapidly. When the activity against GABA was defined as 100%, the purified GABase activity against 5-aminovaleric acid having a similar structure to GABA showed 47.7% and GABase activity against ${\beta}$-alanine, ${\varepsilon}$-amino-n-caproic acid, $_L$-ornithine, $_L$-lysine, and $_L$-aspartic acid showed between 0.3 to 2.3%. The GABA content was analyzed with this co-expressed GABase, compared with the other GABase which was available commercially. As a result, the content of GABA extracted from brown rice, dark brown rice, and black rice were $26.4{\pm}3.5$, $40.5{\pm}4.7$ and $94.7{\pm}9.3{\mu}g/g$, which were similar data of other GABase in the error ranges.

• Molecular & Cellular Toxicology
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• 제5권4호
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• pp.317-322
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• 2009

Hepatic fibrosis is one of chronic liver diseases which spread in worldwide and it has high risk to turn advanced cirrhosis and hepatocellualr carcinoma. Brassica family has been produced for commercial purpose and in Korea Brassica rapa (Turnip) is cultivated in Ganghwa County, Gyeonggi-do Korea and used for making Kimchi. Recently pharmacological effects of turnip have been known; diabete mellitus modulation, alcohol oxidization, and fibrosis inhibition. In previous study we found antifibrogenic effect of turnip water extract and in this study we made turnip nanoparticle to promote turnip delivery into liver. At the same time we assessed the biological safety of turnip nanoparticle. Thioacetamide (TAA) induced hepatic nodular formation and fibrosis (mean of fibrosis score: 4). However, 1% turnip nanoparticle inhibited TAA-induced hepatic nodular formation and fibrosis (mean of fibrosis score: 2-3). Activities of serum enzymes (aspartic acid transaminase (AST), alanine transaminase (ALT), and total bilirubin (T-Bil)), complete blood count (CBC), and the appearance of organs were not different from control and 1% turnip nanoparticle treatment. Conclusively 1% turnip nanoparticle significantly reduced TAA-induced hepatic fibrosis and was safe in 7-weeks feeding.