• Title/Summary/Keyword: protein stability

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Nutritive Value and Functional Properties of Protein Concentrate Fractionated from Chrysanthemum Flowers

  • Park, Nan-Young;Park, Yong-Jin;Kwon, Joong-Ho
    • Preventive Nutrition and Food Science
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    • v.3 no.2
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    • pp.175-179
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    • 1998
  • Some functional properties and nutritive value were determined for the protein concentrated fractionated from chrysanthemum flower in orer to renew interest in the flowers as food. Proximate components of chrysanthemum flower protein concentration (FPC) showed 61.2% protein, 2.0% fat and 35.2% carbhydrate on a dry basis. In amino acid composition of FPC, glutamic acid was the highest in the content, follwoed by aspartic acid, leucine and lysine. The ratio of essential/ total amino acids(E/T) was 0.42, showing a higher level of essential amino acids compared to the FAO reference protein. Digestibility of chrysanthemum FPC by pepsin and trypsin was lwoer than that of casein and was negatively correlative to both water and fat absorptions. Similar characteristics were determined between chrysanthemum FPC and milk casein in their emulsifying activity and emulsion stability. This results indicate that flowers or petals of chrysanthemum might be developed as a good source of protein.

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Molecular analysis of c-terminus structure for elucidating the stabilization effect of site-specific immobilization

  • Baek, Seung-Pil;Yu, Yeong-Jae
    • 한국생물공학회:학술대회논문집
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    • 2001.11a
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    • pp.886-889
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    • 2001
  • C-terminus specific immobilization often results in a increased structural stability resistant to various denaturation factors. In order to elucidate the immobilization effect on the c-terminus in molecular level, we made over 200 protein data set from Protein Data Bank(PDB), analyzed c-terminus structure of each protein, and investigated the structural relationship with the stabilizing factors such as hydrogen bond, ion pairs, cation pi, disulfide bond, solvation free energy, surface area, flexibility and so on.

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Stability and Folding of a Mutant Ribose Binding Protein of Escherichia coli

  • Kim, Joon-Sik;Kim, Hyoungman
    • Proceedings of the Korean Biophysical Society Conference
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    • 1996.07a
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    • pp.25-25
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    • 1996
  • A mature mutant ribose binding protein (RBP) of Escherichia coli was obtained by site-directed mutagenesis, replacing Thr-3 in the N-domain of wild-type mature RBP (WT -mRBP) with a Trp residue (N- Trp-mRBP). The equilibrium unfolding properties and the refolding kinetics of this protein were monitored by fluorescence and circular dichroism (CD). (omitted)

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Modification of Hepatic Microsomal Cytochrome P450 2E1 Enzyme by Garlic Powder in Rat Hepatocarcinogenesis

  • Park, Kyung-Ae;Choi, Hay-Mie
    • BMB Reports
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    • v.30 no.1
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    • pp.73-79
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    • 1997
  • This study was designed to investigate the effects of dietary garlic powder on cytochrome P450 enzymes and membrane stability in murine hepatocarcinogenesis initiated by diethylnitrosamine (DEN). Male Sprague-Dawley rats received a single intraperitoneal injection of DEN (200 mg/kg body wt) dissolved in saline. After 2 weeks on a basal diet, animals were fed diets containing 0. 0.5. 2.0. or 5.0% garlic powder for 6 weeks, and were subjected to two-thirds partial hepatectomy. The areas of placental glutathione S-transferase (GST-P) positive foci were inhibited in rats fed with garlic diets. GST-P is the most effective marker for DEN-initiated lesions. Hepatic microsomal lipid peroxidation was significantly decreased in rats fed with 2.0 and 5.0% garlic powder diets compared with that observed in the control animals and hepatic microsomal glucose 6-phosphatase (G6Pase) activity was found to increase significantly in rats fed 0.5 and 2.0% garlic powder diets. Thus as little as 0.5% garlic powder has a positive effect on the stability of hepatic microsomal membranes. p-Nitrophenol hydroxylase (PNPH) activity and the level of cytochrome P450 2E1 protein in the hepatic microsomes from rats fed diets containing 2.0 and 5.0% garlic powder were much lower than those of control microsomes. Rats fed 5.0% garlic powder diets exhibited the lowest P450 2E1 activity and protein levels among groups. Pentoxyresorufin O-dealkylase activity and immunoblot (cytochrome P450 2B1) analyses were not different between groups. However, the levels of cytochrome P450 1A1/2 protein in rats fed 0.5 and 2.0% garlic powder were significantly induced compared to controls. These results suggest that 2.0% garlic powder is effective in inhibiting the areas of GST-P positive foci, modulating certain isoforms of cytochrome P450 enzymes and stabilizing the hepatic microsomal membrane. Thus, the selective modification of cytochrome P450 enzymes and membrane stability by dietary garlic powder may influence areas of GST-P positive foci and chemoprevention of post-initiation of rat hepatocarcinogenesis.

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Effects of Emulsion Mapping in Different Parts of Pork and Beef (우육 및 돈육 부위에 따라 고기 유화물의 유화맵에 미치는 영향)

  • Choi, Yun-Sang;Jeong, Tae-Jun;Hwang, Ko-Eun;Kim, Hyun-Wook;Kim, Cheon-Jei;Sung, Jung-Min;Oh, Nam-Su;Kim, Young-Boong
    • Korean journal of food and cookery science
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    • v.31 no.3
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    • pp.241-247
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    • 2015
  • This study was conducted in order to evaluate emulsion mapping between emulsion stability and moisture content, cooking yield, hardness, protein solubility, apparent viscosity, and overall acceptability of pork or beef emulsion batters. The pork and beef emulsion batters were added to different parts of the meat. The formulations indicating low emulsion stability and high cooking yield were T1 (pork shoulder), T2 (pork ham), and T5 (beef tenderloin) treatments. Low stability, low hardness and protein solubility were also T1 (pork shoulder), T2 (pork ham), and T5 (beef tenderloin) treatments. The Pearson's correlation coefficients show that emulsion stability is negatively correlated with cooking yield (p<0.05), with a value of -0.90, and positively correlated with hardness (p<0.05), and protein solubility (p<0.01) with values of 0.65 and 0.59, respectively. This approach has been found to be particularly useful for highlighting differences among the emulsified properties in emulsion meat products. Therefore, the results obtained with emulsion mapping are useful in the making of new emulsified meat products of the desired quality.

Effects of Gelatin Hydrolysates Addition on Technological Properties and Lipid Oxidation of Cooked Sausage

  • Ham, Youn-Kyung;Song, Dong-Heon;Noh, Sin-Woo;Gu, Tae-Wan;Lee, Jae-Hyeok;Kim, Tae-Kyung;Choi, Yun-Sang;Kim, Hyun-Wook
    • Food Science of Animal Resources
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    • v.40 no.6
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    • pp.1033-1043
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    • 2020
  • This study investigated the impacts of gelatin hydrolysate addition on the technological properties and lipid oxidation stability of cooked sausage. Gelatin hydrolysate was prepared from pork and duck skin gelatin, through stepwise hydrolysis using collagenase and pepsin. The cooked sausages were formulated without gelatin (control) or with 1% pork skin gelatin, 1% duck skin gelatin, 1% pork skin gelatin hydrolysate, and 1% duck skin gelatin hydrolysate. The pH, color characteristics, protein solubility, cooking loss, and textural properties of cooked sausages were evaluated, and the 2-thiobarbituric acid reactive substances (TBARS) value was measured weekly to determine lipid oxidation stability during 4 wk of refrigerated storage. Enzymatic hydrolysis of gelatin decreased protein content and CIE L* but increased redness and yellowness (p<0.05). When 1% gelatin or gelatin hydrolysate was incorporated in cooked sausage, however, little to no impacts on pH value, moisture content, protein content, color characteristics, protein solubility, and cooking loss were found (p>0.05). The addition of 1% duck skin gelatin hydrolysate increased the cohesiveness and chewiness of cooked sausages. The inclusion of 1% duck skin gelatin accelerated lipid oxidation of cooked sausages during refrigerated storage (p<0.05), whereas duck skin gelatin hydrolysate caused a lower TBARS value in cooked sausage compared to duck skin gelatin. The results show comparable effects of gelatin and gelatin hydrolysate addition on the technological properties of cooked sausages; however, the oxidative stability of raw materials for gelatin extraction should be evaluated clearly in further studies.

Frozen Stability of Proteins Recovered from Fish Muscle by Alkaline Processing (알칼리 공정으로 회수한 어육 단백질의 동결 안정성)

  • Hur, Sung-Ik;Lim, Hyeong-Soo;Kim, Jong-Hyun;Choi, Yeung-Joon
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.35 no.7
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    • pp.903-907
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    • 2006
  • Frozen stability of proteins recovered from white croaker and jack mackerel have been tested by measuring oxidation of residual lipid, browning, total plate count, and texture of gel during storage at $-20^{\circ}C$. The oxidation of residual lipid in recovered protein from Jack mackerel increased up to 60 days, and then decreased. Both browning values significantly was increased after 90 days. Total plate count was $1.2{\times}10^4\;CPU/g$ for proteins recovered from white croaker and $3.2{\times}10^4\;CPU/g$ for proteins recovered from jack mackerel in 60 days. The breaking force, deformation, and whiteness of gel formed from proteins recovered from white croaker did not change up th 120 days significantly, while proteins recovered from jack mackerel did not form heat-induced gel in 120 day. Frozen storage of the recovered protein was limited to 90 days for white croaker and to 60 days for jack mackerel considering the gelling ability and textural properties.

GIGANTEA Regulates the Timing Stabilization of CONSTANS by Altering the Interaction between FKF1 and ZEITLUPE

  • Hwang, Dae Yeon;Park, Sangkyu;Lee, Sungbeom;Lee, Seung Sik;Imaizumi, Takato;Song, Young Hun
    • Molecules and Cells
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    • v.42 no.10
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    • pp.693-701
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    • 2019
  • Plants monitor changes in day length to coordinate their flowering time with appropriate seasons. In Arabidopsis, the diel and seasonal regulation of CONSTANS (CO) protein stability is crucial for the induction of FLOWERING LOCUS T (FT) gene in long days. FLAVIN-BINDING, KELCH REPEAT, F-BOX 1 (FKF1) and ZEITLUPE (ZTL) proteins control the shape of CO expression profile antagonistically, although regulation mechanisms remain unknown. In this study, we show that GIGANTEA (GI) protein modulates the stability and nuclear function of FKF1, which is closely related to the stabilization of CO in the afternoon of long days. The abundance of FKF1 protein is decreased by the gi mutation, but increased by GI overexpression throughout the day. Unlike the previous report, the translocation of FKF1 to the nucleus was not prevented by ZTL overexpression. In addition, the FKF1-ZTL complex formation is higher in the nucleus than in the cytosol. GI interacts with ZTL in the nucleus, implicating the attenuation of ZTL activity by the GI binding and, in turn, the sequestration of FKF1 from ZTL in the nucleus. We also found that the CO-ZTL complex presents in the nucleus, and CO protein abundance is largely reduced in the afternoon by ZTL overexpression, indicating that ZTL promotes CO degradation by capturing FKF1 in the nucleus under these conditions. Collectively, our findings suggest that GI plays a pivotal role in CO stability for the precise control of flowering by coordinating balanced functional properties of FKF1 and ZTL.