• 한국수산과학회지
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• 제40권1호
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• pp.1-7
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• 2007

The chemical and rheological properties of deproteinated porphyrans from laver Porphyra yezoensis were investigated to obtain basic data for the production of food materials with biological functionality. Deproteinated porphyran was prepared by acid extraction (pH 4.0, $80^{\circ}C$, 4 hr) and successive hydrolysis with 0.5% Alcalase and 0.5% Flavourzyme. The porphyran constituted 10.7% of the dry laver and consisted of 0.6% protein, 14.8% ester sulfate, 3.2% 6-O-methyl galactose, 16.0% 3,6-anhydro-L-galactose, and 67.3% galactose. The effects of concentration and temperature on the apparent viscosity were examined by applying the power law and Arrhenius equations. The porphyran solution showed the typical behavior of a pseudoplastic liquid and the flow behavior index decreased with increasing concentration. The activation energy of the deproteinated porphyran solution at a 1,000 L/s shear rate also increased from $1.4954{\times}10^{4}\;to\;1.9544{\times}10^{4}\;J/kg$ mol with the concentration.

• 한국미생물·생명공학회지
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• 제11권1호
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• pp.15-21
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• 1983

전보에서 분리 동정한 Y-33 균주의 $\beta$-galactosise 효소생산조건을 검토하고 효소를 정제하여 정제효소의 성질을 조사한 결과는 다음과 같다. 1. 효소생산을 위한 최적초발 pH는 7.0이었고 최적온도는 $65^{\circ}C$이었다. 2. 효소는 lactose와 galactose에 의하여 유도되어졌으며 세포내효소이었다. 3. 조효소액을 1차 DEAE-cellulose, 2차 DEAE-cellulose column chromatography 및 Sephadex G-150로 gel filtration하여 정제도가 28.3배, 수율이 15.2%의 정제효소를 얻었다. 4. 정제효소는 polyacrylamide gel 전기 영동에 의하여 순도가 검정되었다. 5. 정제효소의 유당가수분해를 위한 최적작용 온도는 $65^{\circ}C$. pH는 6.5이었다.

• 한국미생물·생명공학회지
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• 제9권4호
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• pp.213-218
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• 1981

순수분리정제된 $\beta$-galactosidase의 분자량은 Sephadex G-200 gel filtration법에서 130,000이며 SDS-polyacrylamide gel electrophoresis에서 130,000외에 70,000이 확인되어 이 효소는 70,000인 2개의 subunit로 구성되어 있다고 판단되었다. 효소의 안정pH는 4.5~7.0이며 효소활성의 최적 pH는 4.7 최적온도는 5$0^{\circ}C$였다. 효소활성 및 안정제로 1가, 2가 금속ion을 필요로 하지않았으며 C $u^{++}$ 1mM에서 59%, galactose 100mM에서 48% 저해되었다. 5% lactose용액, 시유 및 10% skim milk 용액에 이 정제된 $\beta$-galactosidase 10units/$m\ell$를 사용하여 5$0^{\circ}C$에서 4시간 동안 반응시켰을 때 lactose가 각각 69.5%. 88.7% 및 72.6%가 glucose와galactose로 전환된 결과를 얻었다.

• 한국미생물·생명공학회지
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• 제31권2호
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• pp.151-156
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• 2003

토양으로부터 세포외로 $\beta$-galactosidase를 분비 생산하는 방선균 YB-10이 분리되었으며, 분리균의 배양ㆍ형태ㆍ생리적 특성을 조사한 결과 Streptomyces속 균주로 확인되었다. 분리균의 배양상등액을 30%~70% ammonium sulfate로 처리하고 투석하여 얻은 $\beta$-galactosidase를 조효소액으로 사용하였을 때 para-nitrophenyl-$\beta$-D-galactopyranoside (pUP$\beta$Gal)는 pH 6.0과 6$0^{\circ}C$의 반응조건에서 가장 잘 분해되었으며, lactose는 galactose와 glucose로 가수분해되는 것으로 확인되었다. 분리균이 생산하는 $\beta$-galactosidase는 galactose에 의해 lactose와 pNP-$\beta$Gal의 가수분해 활성이 모두 저해되었으나, glucose에 의해서는 lactos의 가수분해 활성만 저해되었다. 특히 pUP-$\beta$Gal의 가수분해 활성은 glucose에 의해 약 1.8배 증진되었다.

• Journal of Microbiology and Biotechnology
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• 제30권7호
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• pp.982-995
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• 2020

A putative multidrug efflux gene, yddA, was cloned from the Escherichia coli K-12 strain. A drug-sensitive strain of E. coli missing the main multidrug efflux pump AcrB was constructed as a host and the yddA gene was knocked out in wild-type (WT) and drug-sensitive E. coliΔacrB to study the yddA function. Sensitivity to different substrates of WT E.coli, E. coliΔyddA, E. coliΔacrB and E. coliΔacrBΔyddA strains was compared with minimal inhibitory concentration (MIC) assays and fluorescence tests. MIC assay and fluorescence test results showed that YddA protein was a multidrug efflux pump that exported multiple substrates. Three inhibitors, ortho-vanadate, carbonyl cyanide m-chlorophenylhydrazone (CCCP), and reserpine, were used in fluorescence tests. Ortho-vanadate and reserpine significantly inhibited the efflux and increased accumulation of ethidium bromide and norfloxacin, while CCCP had no significant effect on YddA-regulated efflux. The results indicated that YddA relies on energy released from ATP hydrolysis to transfer the substrates and YddA is an ABC-type multidrug exporter. Functional study of unknown ATP-binding cassette (ABC) superfamily transporters in the model organism E. coli is conducive to discovering new multidrug resistance-reversal targets and providing references for studying other ABC proteins of unknown function.

• 한국수산과학회지
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• 제30권1호
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• pp.79-87
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• 1997

A study on the processing method of anchovy hydrolysate paste (AHP) was carried out to improve the sensory quality of salted and fermented fish. Homogenized whole anchovy was hydrolyzed using commercial pretenses, Complex enzyme-2000 (CE, Pacific Chem. Co.) and Alcalase (AL, Novo), in a cylindrical vessel with 4 baffle plates and 6-bladed turbine impeller. Optimal pH, temperature, and enzyme concentration for the hydrolysis with CE and AL were $7.0,\;52^{\circ}C,\;7\%$, and $8.0,\;60^{\circ}C,\;6\%$, respectively. The rational amount of water for homogenization, agitation speed, and hydrolyzing time were $100\%\;(w/w)$, 100 rpm, and 210 min, respectively. To make the hydrolysate to paste type, it was effective to mix the additives, such as starch, soybean protein, agar, and carrageenan gum to the hydrolysate 5 min before the end of boiling at $100^{\circ}C$ for 30 min. Minimal NaCl concentration for long-term preservation was $15\%$, and this could be reduced to $12\%$ by adding $5\%$ of KCl. yield of the AHP based on the total nitrogen content was $94.6\~97.0\%,\;and\;86.0\~89.2\%$, of the nitrogen was amino nitrogen. Salinity, pH and histamine content of the AHP prepared with $12\%$ NaCl and $5\%$ KCl were $9.3\~9.9\%,\;6.1\~6.2$, and below 13 mg/100 g, respectively. The AHP was stable at $26{\pm}3^{\circ}C$ for 60 days on bacterial growth, and addition of $0.05\%$ of rosemary (Herbalox) extract was effective to inhibit the lipid oxidation of the AHP during storage.

• 한국미생물·생명공학회지
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• 제17권2호
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• pp.136-141
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• 1989

Streptomyces sp. 4M-2의 생전분 분해효소를 황산 암모니움 염석과 이온교환 크로마토그라피 및 Gel 여과 등으로 비활성이 51.22 RSU/mg, 수율 4.5%로 정제할 수 있었다. 정제효소의 분자량은 102,000이었으며 생옥수수 전분에 대한 Km값은 44.44mg/m1 이었다 정제효소의 작용 최적온도는42$^{\circ}C$, pH는 5.5였고 $Ca^{2+}$와 $Ba^{2+}$의 첨가에 의해 효소활성이 증가되었다. 정제효소는 옥수수 amylose를 가장 잘 분해하고 감자전분도 비교적 잘 분해하였다. 이 효소에 의한 옥수수 생전분의 분해산물은 주로 maltose와 maltotriose였고 소량의 glucose와 oligosaccharide도 검출되었으므로 $\alpha$-amylase 계통의 효소로 추정된다.

• The Korean Journal of Physiology
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• 제22권2호
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• pp.163-177
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• 1988

세포막을 구성하고 있는 지질의 물리학적 성상이 단백질의 세포막 속으로의 삽입과정 및 단백질의 기능에 미치는 영향을 관찰하기 위하여 골격근의 근세망(SR)으로부터 $Ca^{2+}-ATPase$ 단백질을 분리한 후 이를 세포막의 주 구성성분인 포스파티딜콜린(PC)과 포스파티딜에타노라민(PE)의 혼합지질과 재조합(reconstitution)시켰다. 이와같이 인공적으로 재조합된 구조물에서 $Ca^{2+}-ATPase$의 기능을 측정하기 위하여 칼슘지시색소인 아르세나죠III(AIII)를 이용한 분광방법과 방사선동위원소를 이용한 여과법으로 칼슘흡수율을 측정하였고 또한 ATP 가수분해 능력을 측정하였다. 실험결과 칼슘의 흡수율은 포스파티딜코린의 함량이 많은 혼합지질과 재조합시킬 때에 증가하였고, ATP 가수분해 능력은 포스파티딜함량이 25%까지는 포스타피딜코린의 양에 비례하여 증가하였으나 50%이상에서는 약간 감소하는 경향을 보였다. 한편 지질세포막속으로 단백질이 삽입되는 양은 포스파티딜 함량이 25%일 때 최고의 값을 보였으며 함량이 그 이하 또는 이상일 때는 감소하였다. 이상의 실험결과로보아 단백질의 기능은 세포막이 "bilayer" 구조를 갖출때에 증가하고 세포막속으로 단백질이 삽입되는 양은 세포막이 "non-bilayer" 구조를 형성할 때에 증가함을 알 수 있다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.644-648
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• 2005

Dextranase (${\alpha}$-1,6-D-glucan-6-glucanogydrolase:E.C. 3.2.1.11) catalyzes the hydrolysis of ${\alpha}$-(1.6) linkages of dextran. A lsd1 gene encoding an extracellular dextranase was isolated from the genomic DNA of L. starkeyi. The lsd11 gene is a synthetic dextranase (lsd1) after codon optimization for gene expression with Pichia pastoris system. A open reading frame of lsd11 gene was 1827 bp and it was inserted into the pPIC3.5K expression vector. The plasmid linearized by Sac I was integrated into the 5'AOX region of the chromosomal DNA of P. pastoris. The lsd11 gene fragment encoding a mature protein of 608 amino acids with a predicted molecular weight of 70 kDa, was expressed in the methylotrophic yeast P. pastoris by controling the alcohol oxidase-1 (AOX1) promoter. The recombinant lds11 was optimized by using the shake-flask expression and upscaled using fermentation technology. More than 9.8 mg/L of active dextranase was obtained after induction by methanol. The optimum pH of LSD11 was found to be 5.5 and the optimum temperature $28^{\circ}C$.

• 한국축산식품학회지
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• 제31권5호
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• pp.663-667
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• 2011

This study was performed to measure the angiotensin I-converting enzyme (ACE) inhibitory activity of peptide extracts derived from the enzymatic proteolysis of Hanwoo Musculus longissimus (M. longissimus) during cold storage. Thermolysin (80 ppm, w/w) and protease type XIII (100 ppm, w/w) were injected separately or in combination for the enzymatic proteolysis of sarcoplasmic and myofibrillar proteins prior to storage at $5^{\circ}C$ (T1) or at $-1^{\circ}C$ (T2) in a chilling room for 9 days. Beef injected with thermolysin (E2) and thermolysin+protease type XIII (E3) showed a significantly higher degree of hydrolysis at both storage temperatures (p<0.05). During the storage period, T1E2 at day 6 and T1E3 at day 9 showed the strongest ACE inhibitory activity with sarcoplasmic and myofibrillar protein proteolysates. Macromolecules greater than 10,000 Da were removed by ultra filtration, and the filtrates were separated into fractions using gel filtration. Five and three major fractions were collected from S-T1E2-6 and M-T1E3-9 extracts, respectively, and the $4^{th}$ fraction of the S-T1E2-6 extracts showed the highest ACE inhibitory rate of $61.96{\pm}7.41%$.