• Title/Summary/Keyword: protein stability

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Studies on the characteristics of concentrated soy protein (농축 콩단백질 분리 및 추출에 관한 연구)

  • Cha, Seo Hui;Shin, Kyung-Ok;Han, Kyoung-Sik
    • Korean Journal of Food Science and Technology
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    • v.52 no.5
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    • pp.459-466
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    • 2020
  • The purpose of this study was to investigate the nutritional characteristics of selected soybeans grown in Korea to isolate concentrated proteins. Examination of the general characteristics revealed that the pH and apparent density of Phaseolus radiatus L. protein and concentrated Vigna angularis protein were significantly higher than those of other concentrated soy proteins. The water absorption capacity was high for concentrated Pisum sativum L. protein, whereas the oil absorption capacity was high for concentrated Glycine max (L.) Merr. protein. The emulsifying activity and emulsifying stability were higher and significantly higher, respectively, for enriched P. radiatus protein. Considering the functional characteristics of concentrated soy protein, its application as a food material in the meat product industry in Korea may be of potential value.

Effect of Environmental Factors on Protein and Lysine Content of Wheat (소맥(小麥)의 단백질(蛋白質) 및 Lysine함량(含量)에 미치는 환경적(環境的) 변이(變異))

  • Kim, Ze-Uook;Chang, Hak-Gil
    • Applied Biological Chemistry
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    • v.29 no.2
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    • pp.116-121
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    • 1986
  • 869 wheat lines were selected and analyzed for protein and lysine composition. Also, high protein-high lysine wheat were evaluated by stability parameter to determine varietal response to environments. Protein content had highly significant positive correlation coefficient of $0.902^{**}$ with lysine content but negatively correlated with lysine per protein content. Bezostaya and Lancota with low regression coefficient provided relatively low response to environment in protein content, while CI 13449 and Centurk with high regression coefficients (1.0) had a relatively high response. High heritability has been formed for protein $(h^2=0.809)$ and lysine content $(h^2=0.647)$.

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Functional Properties of Acetylated and Succinylated Silkworm Larvae Protein Concentrates (아세틸화와 숙시닐화한 번데기 농축단백질의 기능성)

  • 박정륭;박금순
    • Korean journal of food and cookery science
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    • v.3 no.2
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    • pp.1-8
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    • 1987
  • Eighty eight percent of succinylation at $\varepsilon$-amino group of lysine was obtained from silkworm larvae protein concentrate and it resulted in increased bulk density and fat absorption, improved flavor and color, increased solubility over fivefold. Both emulsifying activity and emulsion stability of the succinylated protein were improved by 30% and emulsifying capacity was enhanced by 4%. Foaming capacity of the succinylated Protein concentrate was improved by 30% and foaming stability improved fivefold. The viscosity of succinylated silkworm larvae protein concentrate was increased at all concentrations and reached the highest at 4~5% of concentations. Acetylation of silkworm larvae protein concentrate caused negligible change in the functional properties studied. Therefore, high emulsification properties of silkworm larvae protein concentrate would be a good protein source for the emulsified foods.

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Elucidating the Dynamic Properties of Globular Protein using Predicted Order Parameters and 15N NMR Relaxation

  • Yi, Jong-Jae;Kim, Won-Je;Rhee, Jin-Kyu;Lim, Jongsoo;Lee, Bong-Jin;Son, Woo Sung
    • Journal of the Korean Magnetic Resonance Society
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    • v.21 no.1
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    • pp.26-30
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    • 2017
  • Dynamic properties of proteins can present key information on protein-ligand and protein-protein interaction. Despite their usefulness, the properties of protein dynamics have not been obtained easily due to protein stability and short-term measurement. Here, it is shown that combined method for analysis of dynamical properties. It utilizes predicted order parameter and NMR relaxation data such as $T_1$, $T_2$, and heteronuclear NOE. The suggested method could be used to know the flexibility of protein roughly without precise dynamical parameters such as order parameters through model-free analysis.

3'-Half of the Thrombopoietin cDNA Confers Higher Expression of Erythropoietin at the RNA Level but Not at the Protein Level

  • Kim, Tae-Won;Ji, Jin Woo;Chang, Ho Gun;Kim, Myoung Ok;Ryoo, Zae Young;Park, In Kook;Kim, Sun Jung
    • Molecules and Cells
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    • v.19 no.2
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    • pp.198-204
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    • 2005
  • Both erythropoietin (EPO) and the short-form thrombopoietin (TPO) were expressed at low levels whereas the long-form TPO was expressed at high levels in transgenic animals. To elucidate the role of carboxy-terminal half of the long-form TPO which is absent in the short-form, we generated recombinant TPO or EPO expression vectors which contain or lack the carboxy-terminal half of TPO and examined their expression in the HC11 and 293 cells. The long-form TPO was expressed higher than the short-form regardless of the cell types, transfection modes, and promoters. When 3'-half of the long-form TPO cDNA was placed downstream of the EPO cDNA to act as a 3'-untranslated region, expression of EPO was moderately increased at the RNA level, however, no remarkable increase was observed at the protein level. These results suggest that the low expression of EPO, as like as the short-form TPO, is due to absence of the 3'-half in the full-length TPO that confers stability both at the RNA and protein levels.

Effect of IPTG Induction on Production of ${\beta}$-Galactosidase-PreS2 Fusion Protein in Recombinant Escherichia coli

  • Nam, Soo-Man;Park, Young-Hoon
    • Journal of Microbiology and Biotechnology
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    • v.1 no.4
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    • pp.274-280
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    • 1991
  • Effects of IPTG induction on cell growth and production of ${\beta}$-galactosidase-preS2 fusion protein (${\beta}$gal-preS2) were studied in a defined medium using a recombinant Escherichia coli JM109/pCMHB30. IPTG was added (0.2 mM) to induce the cloned-gene expression in the early-, mid-, and late-log growth phases. The most serious decreases in growth rate and plasmid stability were observed for the induction in the early-log growth phase. The expression level of ${\beta}$gal-preS2 attained by the induction in the mid-log phase was about 0.51 mg fusion protein/mg total cellular protein, which was 2- and 5-fold improvement over the levels obtained with the inductions in the early- and late-log phases. Formation of acidic byproducts including acetate and pyruvate showed different profiles during the fermentation period for each cases of induction; pyruvate was the major byproduct for the induction in the early-log phase while acetate production became more significant for the cases of inductions in the mid- and late-log phases.

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Biochemical and NMR Characterization of MTH1880 Mutant Proteins for Folding-Unfolding Studies

  • Kim, Hee-Youn;Ryu, Soo-Young;Yun, Ji-Hye;Kim, Suhk-Mann;Chang, Ik-Soo;Lee, Weon-Tae
    • Bulletin of the Korean Chemical Society
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    • v.31 no.12
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    • pp.3521-3524
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    • 2010
  • MTH1880 is a hypothetical protein derived from Methanobacterium thermoautotrophicum, thermophilic methanogen. The solution structure determined by NMR spectroscopy showed that it has a novel $\alpha+\beta$-fold with a highly acidic ligand binding pocket. Since MTH1880 maintains its ultra-stable structural characteristics at both high temperature and pressure, it has been considered as an excellent model for studying protein folding. To initiate the structural and folding study of MTH1880 in proving its unusual stability, we performed the site directed mutagenesis and biochemical analysis of MTH1880 mutants. Data from circular dichroism and NMR spectroscopy suggest that the point mutations perturbed the structural stability of protein even though the secondary structure is retained. This study will provide the useful information in understanding the role of participating residues during folding-unfolding process and our result will be used in designing further folding experiments for hyper-thermopile proteins like MTH1880.

Effects of Protein Sources on Kimchi Fermentation and on the Stability of Ascorbic Acid (단백질(蛋白質) 급원(給源) 식품(食品)이 김치의 발효와 Ascorbic Acid의 안정도(安定度)에 미치는 영향(影響))

  • Lee, H.S.;Ko, Y.T.;Lim, S.J.
    • Journal of Nutrition and Health
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    • v.17 no.2
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    • pp.101-107
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    • 1984
  • Effects of protein-sources on Kimchi fermentation and on the stability of ascorbic acid were investigated at $7{\pm}1^{\circ}C.$ Kimchi samples with various protein sources showed the higher pH and total acidity through the fermentation period than kimchi without the proteins. The results revealed that the proteins have acted as good buffer and lactobacilli-growth enhancer in the fermentation, and the milk proteins showed the most significant effect among the samples. The lactobacilli were at the highest growth at 15th day in all the samples. The amounts and changes in ascorbic acid content during the fermentation did not differ significantly between the control and protein added samples. The fresh, unfermented kimchi contained 14.5-15.7mg of ascorbic acid per 100g of sample and decreased continuously by the 12th day of fermentation. After then the vitamin increased in all the samples and then again decreased slowly after 18th day. The contents of ascorbic acid at the end of the 3 weeks-fermentation(16.3-17.3mg/100g) were still higher than the contents of fresh, unfermented kimchi.

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Thermal Stabilization of Aspergillus phytase by L-Arginine

  • Sunghoon Ryu;Park, Tae-Gwan
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.3 no.1
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    • pp.32-34
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    • 1998
  • Phytase from Aspergillus species is a very heat unstable enzyme which inactivates to a great extent during the thermal processing of animal feed formulation. Various protein stabilization additives were tested to improve its heat stability. Among them, a basic amino acid, L-arginine remarkably increased the thermal stability of phytase in an aqueous solution state.

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