• 한국식품영양학회지
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• 제3권1호
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• pp.57-68
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• 1990

In order to obtain the fundamental informations on cellulase of Trichoderma viride QM 9414 for its production and utilization, some physico-chemical properties of the enzyme were reviewed. When T. viride QM 9414 was cultured on wheat bran medium, filter paper-disintegrating and carboxymethyl cellulose-saccharifying activity were increased with the cell growth, and thereafter CMC-saccharifying activity was kept on almost the same leved while filter-paper disintegrating activity was decreased sharply. And B-glucosidase was formed maximally on the late stationary phase of growth. The crude cellulase of cell-free extracts was purified by (NH4)2SO4 fractionation, Sephadex-G 200 column chromatography and DEAE Sephadex A-50 column chromatography. Filter paper-disintegrating, CMC-saccharifying and B-glucosidase activity were purified 10-fold, 47-fold and 38-fold, respectively. The crude enzyme was proved to be a complex of three different enzyme proteins which were showing filter paper-disintegrating, CMC-saccharifying and B-glucosidase activity. The optimal pH of the three enzyme components was alike pH 4.0, and the optimal temperature for CMC-saccharifying, filter paper-disintegrating and B-glucosidase activity were 4$0^{\circ}C$, 45$^{\circ}C$ and 5$0^{\circ}C$ respectively. The Km and Vmax values of CMC saccharifying activity for CMC were 0.485% and 3.10, and the Km and Vmax vallues of B-glucosidase for PNPG were 0.944$\times$10-3M and 0.097, respectively. The Km and Vmax values of filter paper-disintegrating activity for Avicel were determined to be 0.09% and 0.178, respectively. B-Glucosidase activity was competitively inhibited by glucose, and the Ki value for this enzyme was 3.54$\times$10-3M, CMC saccharifying activity was found to be greatly inhibited by cellobiose.

• 한국식품영양과학회지
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• 제18권3호
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• pp.348-355
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• 1989

Alkaline protease 생성능이 강한 Aspergillus fumigatus 균주를 토양에서 분리하고, 생성효소를 정제하여 특성을 조사한 결과 최적 pH는 9.0, pH안정성은 $pH\;8.0{\sim}10.0$, 최적온도는 $50^{\circ}C$였으며, $50^{\circ}C$이하의 온도에서 안정하나 그 이상의 온도에서는 급격한 효소 불활성화를 보였고, 금속염 $Mn^{++},\;Cu^{++},\;Ba^{++},\;Mg^{++}$ 등에 의해서 활성이 다소 증대되나 $K^+,\;Fe^{+++},\;Ag^{++},\;Pb^{++},\;Na^+,\;Ca^{++},\;Hg^+,\;Zn^{++}$에 의해 저해를 받았다. 활성저해제인 EDTA, 2,4-DNP, ${\varepsilon}-amino$ caproic acid에는 큰 저해를 받지 않으나, PCMB에 많은 저해를 받는 것으로 미루어 활성 부위가 SH기인 cystein protease로 추정되었다. Km값은 $8.33{\times}10^{-4}mole/{\ell}$, Vmax는 $47.62{\mu}g/min$였으며, casein과 hemoglobin을 trypsin보다 더 잘 분해하고, casein을 hemoglobin보다 잘 분해하였다.

• 한국미생물·생명공학회지
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• 제27권6호
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• pp.466-470
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• 1999

Protease production and its characteristics were investigated with Mucor racemosus f. racemosus PDA 103 which was isolated from Korean traditional meju. Optimum culture conditions of the strain for the production of the protease in basic medium[bean(Baektae):H2O=1:1(w/v)] were as follows: pH 6, 3$0^{\circ}C$ and 72hrs. Optimum pH and temperature for the enzyme activity of the protease produced by Mucor racemosus f. racemosus were pH 5 and 5$0^{\circ}C$, respectively. The enzyme was relatively stable a pH2.0~5.0 and at temperature below 4$0^{\circ}C$. Phenylmethane-sulfonyl fluoride and Ag+ inhibited the enzyme activity. This indicates that the enzyme is serine protease. Km value was 0.9$\times$10-4M and Vmax value was 5.93$\mu\textrm{g}$/min. This enzyme hydrolyzed casein more rapidly than bovine albumin.

• 유기물자원화
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• 제7권2호
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• pp.73-82
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• 1999

사과박의 퇴비화에서 효소활성도가 퇴비의 안정성 혹은 부숙도를 나타내는 지표로서의 사용가능성이 있는지를 검증하기 위해 배양계수법에 의한 미생물군집의 천이와, 무형광상태로 기질에 결합되어있던 형광물질(MUF)이 분해되면서 띠게 되는 형광정도가 해당효소의 활성도에 비례하여 높아지는 것을 이용하여 ${\beta}$-glucosidase와 cellobiohydrolase 활성도를 측정하였다. 탄수화물의 분해에 관여하는 두 효소의 활성도는 시간변화에 따라 점점 낮아졌다. 미생물개체군과 효소활성도간의 상관성은 균류군을 제외하고는 없는 것으로 나타났고 또 균류가 높은 개체수를 나타내는 것으로 보아 균류가 사과박의 퇴비화에 지대한 역할을 담당할 것으로 사료된다.

• 대한한의학회지
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• 제17권2호
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• pp.264-276
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• 1996

This study was carried out to evaluate the effect of Samhwasan on the Na-K-ATPase activity of heart muscle. The Na-K-ATPase activity was prepared from rabbit heart ventricles. Samhwasan markedly inhibited the Na- K - ATPase activity in a dose-dependent manner with an estimated $I_{50}$ of 0.56%. Hill coefficient was 1.70, indicating that the enzyme has more than one binding site for the Samhwasan. Inhibition of enzyme activity by Samhwasan increased as pretreatment time was prolonged. Inhibition by the drug was not affected by a change in enzyme protein concentration. Kinetic studies of substrate activation of the enzyme indicated classical noncompetitive inhibition, showing significant reduction in Vmax without a change in Km value. Inhibitory effect by Samhwasan was not altered by changes in concentration of $Mg^{2+}$, $Na^+$ or $K^+$, dithiothreitol. a sulfhydryl reducing reagent, did not protect the inhibition of Na-K-ATPase activity by Samhwasan combination of Samhwasan and ouabain showed a cumulative inhibition fashion. These results suggest that Samhwasan inhibits Na-K-ATPase activity of heart ventricles with an unique binding site different from that of ATP, $Mg^{2+}$, $Na^+$ or $K^+$ and ouabain.

• 한국식품영양학회지
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• 제14권1호
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• pp.65-68
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• 2001

Bacillus sp. DSNC 101의 배양 상징액으로부터 $\alpha$-L-arabinofuranosidase를 정제하여 그 특성을 조사하였다. 정제된 효소의 분자량을 SDS-PAGE를 이용하여 측정한 결과 56kDa로 나타났으며 효소 활성도에 대한 최적 온도와 최적 pH는 각각 55$^{\circ}C$와 7.0이었다. p-nitrophenyl-alpha-L-arabinofuranoside에 대한 Km 값과 Vmax는 1.0mM과 113.6U/mg이었으며 Hg$^{2+}$과 Cu$^{2+}$의 첨가는 효소 반응을 완전히 저해하였다. Ba-cillus sp. DSNC 101은 탄소원으로 볏짚을 사용할 때 $\alpha$-L-arabinofuranosidase를 생산하였으나 xylan이나 glucose, cellulose를 탄소원으로 배양할 때는 생산되지 않았다.

• 한국식생활문화학회지
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• 제9권2호
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• pp.137-142
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• 1994

돌산갓의 독특한 향미와 잠재된 항균성을 김치의 맛과 저장성 향상에 이용하기 위한 기초자료로서 갓의 myrosinase를 분리 정제하여 그 특성을 밝히고, 갓김치 숙성 중 myrosinase 활성도 변화를 측정하였다. 갓의 myrosinase를 DEAE Sephadex, chromatofocusing 및 Con A Sepharose column chromatography에 의해 정제한 결과 비활성은 7107배 증가하였고 수율은 18.8%였다. 정제된 효소의 최적 pH는 5.9였으며, 등전점은 4.6, 분자량은 약 129 kD, Km은 0.206 mM, Vmax는 $2.039\;{\mu}M{\cdot}min^{-1}{\cdot}mg\;protein^{-1}$로 나타났다. 또한 myrosinase의 activator인 ascorbic acid는 0.6 mM에서 최대 효소활성을 보이다가 그 이후는 점차 효소활성의 감소를 보여 2.0 mM 이상의 농도에서는 효소활성을 거의 완전히 상실시켰다. 갓김치의 저장 중 myrosinase 활성 변화를 측정한 결과 김치 제조 직후에 약 70 nmol/min/mg protein이던 것이 $20^{\circ}C$에서 3일 이상 저장으로 급격히 그 활성을 잃어 4일 후에는 50% 이상의 활성을 손실하고 10일 후에는 거의 활성이 없었다.

• 한국식품저장유통학회지
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• 제6권2호
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• pp.216-220
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• 1999

혹미의 취반과정 중 lipoxygenase 작용에 의해 생성되는 휘발성 향미 성분의 분석을 위한 기초 자료를 제공하기 위해 진도산 흑미의 lipoxygenase activity를 비색법을 이용하여 측정하였다. 20-60% 포화농도의 ammonium sulfate를 첨가하여 활성을 비교한 결과 30% 포화농도에서 23.9 unit/mg으로 가장 높은 활성을 나타내었다. pH 6.0-9.0에서 조효소액의 활성을 측정한 결과 pH 7.0에서 24.97 unit/mg 으로 가장 높게 나타났으며 0.05-0.8 mM의 linoleic acid를 기질로하여 활성을 측정한 후 Lineweaver-Burk plotting으로 해석하여 속도상수 Vmax와 Km을 구한 결과 각각 53.85 unit/mg과 0.21 mM로 나타났다. 저장온도 -4$0^{\circ}C$, 4$^{\circ}C$, $25^{\circ}C$에서 저장하며 활성을 측정한 결과 -4$0^{\circ}C$에서 저장 3일 후 활성이 62%까지 떨어졌으며 $25^{\circ}C$ 저장의 경우에는 저장 4시간 이후로는 활성을 나타내지 않았다. Microwave로 0-100초간 가열처리 후 활성을 측정한 결과 100초간 가열 하였을 때 대조구에 비해 3.25%의 활성만을 나타내었다. 따라서 진도산 흑미의 lipoxygenase activity는 pH 7.0, ammonium sulfate 30% 포화농도, 기질의 농도 0.21 mM에서 측정하는 것이 가장 적합하며 microwave heating 처리에 의해 효소를 불활성화 할 수 있는 것으로 생각되었다.

• The Korean Journal of Physiology
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• 제16권2호
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• pp.111-117
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• 1982

Slices of rat corpora lutea(CL) incubated with. prostaglandin $F_{{2{\alpha}}}(PGF_{2{\alpha}})$ in Krebs-Hensenleit (K-H) Ringer solution showed a decrease in $Na^+-K^+$-ATPase activity after 60 min of incubation. However, $PGF_{2{\alpha}}$ in vitro did not alter $Na^+-K^+$-ATPase activity of isolated luteal membrane fractions. Following $PGF_{2{\alpha}}$ induced in vivo luteal regression, reduction of Vmax an elevation of the activation energy above transition temperature of the lipid phase of the membrane occurred without changes of Km, optimum pH and transition temperature. These results suggest that reduction of $Na^+-K^+$-ATPase activity after $PGF_{2{\alpha}}$ treatment may be due to the reduction of the number of enzyme molecules or to masking of the active site of the enzyme without any change in enzyme characteristics. In addition, a change in membrane bound enzyme activity may be an early step in $PGF_{2{\alpha}}$ induced luleolysis.

• International Journal of Industrial Entomology and Biomaterials
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• 제27권2호
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• pp.322-325
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• 2013

In the present study, we report that the selection of operation mode is important to take the full advantage of nanofibrous membrane in enzyme immobilization. Silk fibroin nanofibrous membrane has been prepared by electrospinning, and a-chymotrypsin was immobilized as a model enzyme. When the immobilized enzyme was operated in the membrane reactor mode, the Michaelis constant, Km, was lower and the Vmax was higher compared to the batch reactor mode. No concentration gradient was observed in the membrane reactor mode and the immobilized enzyme was stable even after 7 times of re-use. Our results suggests that the enzyme immobilized nanofibrous membrane should be operated in the membrane reactor mode rather than in the bath reactor mode.