• 한국식품과학회지
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• 제9권2호
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• pp.123-130
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• 1977

동방유량(東邦流糧)에서 공급(供給)받은 저변성(低變成) 탈지대두박(脫脂大豆粕)을 0.02N NaOH액(液)으로 추출(抽出)하여 Soy Protein Isolate (SPI)의 수율(收率)을 증류수나 염용액(鹽溶液)으로 추출(抽出)할때 보다 높이는 과정(過程)(84 % 수율(收率))을 확립(確立)하였으며 제조(製造)된 SPI는 92.1 %의 단백질(蛋白質)을 함유(含有)하였다. SPI를 $70^{\circ}C$에서 moisture heat를 하면 80분간(分間)에 5 %의 변성(變性)이 일어났으나 $95^{\circ}C$에서는 20분(分) 처리(處理)에 의(依)하여 95 %의 변성(變性)이 일어났다. SPI의 alkali 현탄액 (dope solution)은 SPI의 농도(濃度) 15 %, NaOH 농도(濃度) 0.6 %일때 7분(分)만에 60 poises를 나타내고 계속 안정(安定)된 점도(粘度)를 유지하였다. NaOH의 농도(濃度)가 0.9 %일 때는 시간(時間)이 경과(經過)함에 따라 점도(粘度)는 증가(增加)하였다가 감소(減少)하는 경향(傾向)을 보였다. syringe needle (dia. 0.3 mm)로서 모의(模擬) 실험(實驗) 결과(結果) 점도(粘度)가 $28^{\circ}C$에서 60 Poises일때 가장 적합한 단백질섬유(蛋白質纖維)의 texture를 보여주었다. 가열(加熱)에 의(依)한 SPI의 gelation은 8 %이상(以上)의 SPI농도(濃度)일 때 gel이 형성(形成)되기 시작하였으며 $100^{\circ}C$까지 안정(安定)한 gel을 형성(形成)하였고 SPI의 농도(濃度)가 12 %일때 $120^{\circ}C$에서 30분(分) 가열(加熱)에 의(依)하여 20,000 Poises의 좋은 점도(粘度)를 가졌으나 $120^{\circ}C$이상에서는 gel의 continuity가 떨어져 과립상(果粒上)의 gel이 생성(生成)되었다. SPI의 유화력(乳化力)은 pH가 8.7, NaCl의 농도(濃度)가 2 %일때 가장 큰 유화력(乳化力)을 나타냈다. milk casein과 비교(比較) 실험(實驗) 결과(結果) 유화력(乳化力)은 약간 낮았으나 염(鹽)이 존재(存在)하는 경우는 근사한 유화력(乳化力)을 보였다. 그러나 SPI의 foaming capacity는 foaming stability 면(面)에서 egg albumin이나 milk casein과 비교(比較)하여 양호(良好)한 결과(結果)를 보여주었다.

• Journal of Microbiology and Biotechnology
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• 제27권10호
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• pp.1837-1843
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• 2017

Knowledge of avian host responses to brucellosis is critical to understanding how birds resist this infection; however, this mechanism is not well established. On the other hand, temperature has a major involvement in the physiology of living organisms, and cell death induced by heat is attributed to protein denaturation. This study demonstrates the direct bactericidal effect of a high temperature ($41^{\circ}C$) on Brucella abortus that resulted in the gradual reduction of intracellular bacteria and inhibited bacterial growth within avian macrophage HD11 in an increasing period of time. On the other hand, this study also revealed that high temperature does not affect the rate of bacterial uptake, as confirmed by the bacterial adherence assay. No significant difference was observed in the expression of target genes between infected and uninfected cells for both temperatures. This study suggests the susceptibility of B. abortus to bacterial death under a high temperature with an increased period of incubation, leading to suppression of bacterial growth.

• Journal of Microbiology and Biotechnology
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• 제16권3호
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• pp.457-464
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• 2006

Three extracellular proteases (Vpr, peptidase T, and subtilisin) were identified from the culture supernatant of Bacillus subtilis KCTC 3014. All the proteins were partially purified as a mature form by using a DEAE-cellulose ion-exchange column chromatography. Their activities were determined by using zymography and densitometry. The relative molecular masses of Vpr and peptidase T (PepT) were determined to be 68 and 48 kDa by SDS-PAGE and zymography, respectively. However, subtilisin formed a 'binding mode' at the top of the separating gel. After denaturation by boiling at $100^{\circ}C$ for 5 min, its molecular mass was determined to be 29 kDa, whereas its activity was lost. The optimal pH of Vpr, PepT, and subtilisin were 9.0, 6.0-7.0, and 7.0-8.0, respectively. The optimal temperature of Vpr, PepT, and subtilisin was 40, 50, and $40^{\circ}C$, respectively. Inhibitor test revealed that Vpr and subtilisin were serine proteases and that PepT was a metalloprotease. Interestingly, we found that Vpr showed no enzyme activity on a 2DE zymogram gel. Three genes, vpr, pepT, and apr (encoding subtilisin protein), were cloned and their nucleotide and deduced amino acid sequences were determined.

• Journal of Microbiology and Biotechnology
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• 제23권11호
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• pp.1560-1568
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• 2013

Salmonella, a main cause of foodborne diseases, encounters a variety of environmental stresses and overcomes the stresses by multiple resistance strategies. One of the general responses to hyperosmotic stress is to import or produce compatible solutes so that cells maintain fluid balance and protect proteins and lipids from denaturation. The ProP and ProU systems are the main transport systems for compatible solutes. The OsmU system, recently identified as a third osmoprotectant transport system, debilitates excessive growth as well by reducing production of trehalose. We studied a fourth putative osmoprotectant transport system, YehZYXW, with high sequence similarity with the OsmU system. A Salmonella strain lacking YehZ, a predicted substrate-binding protein, did not suffer from hyperosmolarity but rather grew more rapidly than the wild type regardless of glycine betaine, an osmoprotectant, suggesting that the YehZYXW system controls bacterial growth irrespective of transporting glycine betaine. However, the growth advantage of ${\Delta}yehZ$ was not attributable to an increase in OtsBA-mediated trehalose production, which is responsible for the outcompetition of the ${\Delta}osmU$ strain. Overexpressed YehZ in trans was capable of deaccelerating bacterial growth vice versa, supporting a role of YehZ in dampening growth. The expression of yehZ was increased in response to nutrient starvation, acidic pH, and the presence of glycine betaine under hyperosmotic stress. Identifying substrates for YehZ will help decipher the role of the YehZYXW system in regulating bacterial growth in response to environmental cues.

• 한국식품과학회지
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• 제38권3호
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• pp.444-447
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• 2006

마를 냉동건조, 선풍기건조, 열풍건조, 연탄건조한 후 이들의 현탁액과 상징액의 점도와 첨가물에 따른 점도변화를 조사하였다. 선풍기건조한 마 현탁액(7.5%)의 점도는 43 mPa s로 냉동건조한 것의 58.1 mPa s보다는 낮았지만 시중에서 많이 사용하는 열풍건조한 것의 17.2 mPa s보다는 높았다. 이는 농가에서 저렴한 방법으로 점성이 상당히 유지되는 건조마를 생산할 수 있음을 말해준다. 건조방법 별로 점도차이가 나는 것은 건조 중 점질물의 단백질이 열변성되었기 때문이었다. 마현탁액과 상징액에 설탕을 첨가하면 점도가 상승하였으나 소금의 첨가로는 별 영향이 없었다. 구연산은 0.5% 첨가하였을 때 점도가 감소하였다.

• 한국연초학회지
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• 제21권2호
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• pp.160-170
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• 1999

Purification and biochemical experiments on the carboxylesterases-III (CE-III) from the indian meal moth, Plodia interpunctella (Hubner) were carried out to understand their enzymemological characteristics. The CE-III from the fifth instar larvae was purified by means of ammonium sulfate fractionation, gel permeation choromatography and ion exchange choromatography. The optimal temperature for the reaction of the CE-III on the 4 substrates ($\alpha$-Na, $\alpha$-Nb, $\beta$-Na and $\beta$-Nb) was confirmed at 4$0^{\circ}C$. The optimal pH for the reactions on the substrates $\alpha$-Na and $\alpha$-Nb was 7.5. But the optimal pH on the substrate $\beta$-Na and $\beta$-Nb was 8.0. The optimal substrate concentration for the reactions of the CE-III was 3.16 X 10$^{-3}$ M in $\alpha$-Na and $\beta$-Nb. On the substrate $\beta$-Na and $\alpha$-Nb, the optimal substrate concentration was 1.0 X 10$^{-3}$ M for CE-III. The $V_{max}$ and $K_{m}$ values of the carboxylesterases were varied by the substrates as followings: the $V_{max}$ of CE-III was 45.9 for $\alpha$-Na, 52.6 for $\beta$-Na, 36.4 for $\alpha$-Nb, and 83.3 ($\mu$ mol/min/mg protein) for $\beta$-Nb. The $K_{m}$ of CE-III was 1.43 X 10$^{-4}$ M for $\alpha$-Na, 3.57 x 10$^{-5}$ M for $\beta$-Na, 9.17 X 10$^{-5}$ M for $\alpha$-Nb, and 7.14 X 10$^{-5}$ M for $\beta$ -Nb, respectively. The CE-III seemed to have somewhat high thermostability considering that the temperature for effective denaturation on activity was about 5$0^{\circ}C$ ～ 6$0^{\circ}C$.EX>.EX>.

• Journal of the Korean Wood Science and Technology
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• 제29권3호
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• pp.112-122
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• 2001

Laccase enzymes from Cerrena unicolor and Trametes versicolor were immobilized on the activated glass beads (CPG), silica gel (SG) and soil (SL). The heterogeneous matrices were activated by ${\gamma}$-aminopropyltriethoxysilane (APTES) and glutaraldehyde (GA), and their surfaces were coated by keratin (KER) on activated or non-activated CPG, SG and SL. The laccase activities were tested in the aqueous solution for the native and immobilized preparations using different pH and temperature conditions. By keratin coating on supports, in the cases of CPG-KER and SL-KER, the immobilization yield was increased from about 80% to 90%. Moreover, much less protein was immobilized in keratin coated matrices than in inorganic ones alone (e.g. on CPG-KER 57.6%, whereas on CPG alone 80.6%). Laccase immobilization on keratin coated inorganic matrices was generally more effective than that of non-coated matrices. Concerned to pH dependency, the optima pH for immobilized laccases generally shifted towards to higher values, 5.5-5.8 and even 5.9 in the case of keratin for C. unicolor and from 5.3 to 5.7 for T. versicolor, respectively, and decreased less gradually both in acidic and alkaline regions. The immobilized laccase was more stable against thermal denaturation. This seems particularly true at $75^{\circ}C$ in the case of C. unicolor, where the activity of immobilized enzyme is > 50% higher than that of the free enzyme. For T. versicolor the respective values were $65^{\circ}C$, and 50%.

• Molecules and Cells
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• 제38권2호
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• pp.187-194
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• 2015

Thioredoxin (TRX) is a disulfide reductase present ubiquitously in all taxa and plays an important role as a regulator of cellular redox state. Recently, a redox-independent, chaperone function has also been reported for some thioredoxins. We previously identified nodulin-35, the subunit of soybean uricase, as an interacting target of a cytosolic soybean thioredoxin, GmTRX. Here we report the further characterization of the interaction, which turns out to be independent of the disulfide reductase function and results in the co-localization of GmTRX and nodulin-35 in peroxisomes, suggesting a possible function of GmTRX in peroxisomes. In addition, the chaperone function of GmTRX was demonstrated in in vitro molecular chaperone activity assays including the thermal denaturation assay and malate dehydrogenase aggregation assay. Our results demonstrate that the target of GmTRX is not only confined to the nodulin-35, but many other peroxisomal proteins, including catalase (AtCAT), transthyretin-like protein 1 (AtTTL1), and acyl-coenzyme A oxidase 4 (AtACX4), also interact with the GmTRX. Together with an increased uricase activity of nodulin-35 and reduced ROS accumulation observed in the presence of GmTRX in our results, especially under heat shock and oxidative stress conditions, it appears that GmTRX represents a novel thioredoxin that is co-localized to the peroxisomes, possibly providing functional integrity to peroxisomal proteins.

• Carbon letters
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• 제8권3호
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• pp.184-190
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• 2007

Carbon Nano Tubes could be either metallic or semi-conducting in nature, depending on their diameter. Its photocatalytic behavior has given an impetus to use it as an anti-microbial agent. More than 95% Escherichia coli and Staphylococcus aureus bacteria got killed when exposed to Carbon Nano Tubes for 30 minutes in presence of sunlight. Carbon Nano Tubes are supposed to have smooth surface on to which it accumulates positive charges when exposed to light. The surface that is non illuminated has negative charge. At the cellular level microorganisms produce negative charges on the cell membrane, Therefore damaging effect of multi walled carbon nano tubes (exposed to light) on the microorganisms is possible. In this paper, photo catalytic killing of microbes by multi walled carbon nano tubes is reported. Killing was due to damage in the cell membrane, as seen in SEM micrographs. Moreover biochemical analysis of membrane as well as total cellular proteins by SDS PAGE showed that there was denaturation of membrane proteins as well as total proteins of both the microbes studied. The killed microbes that showed a decrease in number of protein bands (i.e. due to breaking down of proteins) also showed an increase in level of free amino acids in microbes. This further confirmed that proteins got denatured or broken down into shorter units of amino acids. Increased level of free amino acids was recorded in both the microbes treated with multi walled carbon nano tubes and sunlight.

• Journal of Plant Biotechnology
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• 제5권2호
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• pp.83-86
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• 2003

A reverse transcription polymerase chain reaction (RT-PCR) protocol was developed using two specific 22-mer primers located in coat protein gene of SPFMV. A 411 bp PCR-product was detected in virus infected plants as well as tissue culture raised sweet potato but not in healthy plants. For optimization of RT-PCR protocol, the optimum crude nucleic acid concentration, annealing temperature, primer concentration and numbers of PCR-cycle for maximum sensitivity and specificity were determined. The optimum condition for RT-PCR was as follows: RT-PCR reaction mixture was one-step mixture, containing 50 pmol of primer, 30 units of reverse transcriptase, 5 units of RNasin, and the crude nucleic acid extracts (200 ng). In RT-PCR, cDNA was synthesized at $42^{\circ}C$ for 45 min before a quick incubation on ice after pre-denaturation at $95^{\circ}C$ for 5 min. The PCR reaction was carried out for 40 cycles at $96^{\circ}C$ for 30 see, $63^{\circ}C$ for 30 sec, $72^{\circ}C$ for 1 min, and finally at $72^{\circ}C$ for 10 min. The viral origin of the amplified product was confirmed by sequencing, with the sequence obtained having $95-98\%$ homology with published sequence data for SPFMV. The benefits of this RT-PCR based detection of SPFMV would be simple, rapid and specific.