• Title/Summary/Keyword: Protein stability

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A Study on the Effect of Mungbean Protein on Quality Characteristics of Angel Parfiet (녹두 단백질을 첨가하여 조리한 Angel Parfiet의 특성에 관한 연구)

  • 민성희;손경희
    • Korean journal of food and cookery science
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    • v.9 no.4
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    • pp.308-311
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    • 1993
  • This study was carried out in order to study the effect of mungbean protein on quality characteristics of angel parfait. The foaming properties of mungbean protein was tested and angel parfait was made with mungbean protein. The results were as follows: 1. Foam expansion values of mungbean protein were generally dependent on protein concentration to 3かio protein suspension. From 1% to 3% suspen-sion, foam expansion values increased. However, over 3% suspension, the values decreased. 2. The foaming stability appeared the greatest value as protein concentration increased. But it was not signifi-cantly different over than 5% concentration. 3. The overrun of angel parfait made with munbean protein was significantly higher than that of made with soybean protein and sensory evaluation data presented that angel parfait made with mungbean protein was significantly higher than that of soybean protein.

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Effect of Phytase, Protease and the Mixed Enzyme of Phytase and Protease on the Extraction and Properteis of the Protein from Abolished Soybean Meal (Phytase, Protease 및 Phytase와 Protease 혼합 효소처리가 폐대두박의 단백질 추출율 및 그 기능성에 미치는 영향)

  • 조영제;천성숙
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.29 no.1
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    • pp.57-63
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    • 2000
  • To extract insoluble proteins from abolished soybean meal, the meal was treatesd with phytase and protease produced by Aspergillus sp. SM-15 and Aspergillus sp. MS-18. The extraction of insoluble soybean protein was increased at alkaline range more than pH 5 in case of phytase, pH 7 to 11 in case of protease and pH 5 to 12 in case of the mixed enzyme of phytase and protease. The optimum extraction temperature of insoluble protein was 5$0^{\circ}C$ for phytase and the mixed enzyme of phytase and protease, and 6$0^{\circ}C$ for protease. The optimum treatment time for extraction of protein was 9 hrs for phytase, 11 hrs for protease and the mixed enzyme of phytase and protease and optimum unit of enzyme for extraction of protein was 600 unit, 40 unit and 900 unit+60 unit in case of phytase, protease, phytase and protease, respectively. The treatment of mixed enzyme showed higher extracton rate of protein than single enzyme treatment. The foaming capacity, foaming stability, emulsion capacity, and emulsion stability of soybean meal protein by the treatment of the enzymes increased at all pH range. Further more oil absorption as well as water absorption capacities by the treatment of the enzymes were also increased. The functional properteis of the soybean meal protein treated by the mixed enzyme were higher than those of soybean meal protein treated by the single enzyme.

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Structural stability of CD1 domain of human mitotic checkpoint serine/threonine-protein kinase, Bub1

  • Kim, Hyun-Hwi;Song, Hyun-Kyu;Lee, Bong-Jin;Park, Sung Jean
    • Journal of the Korean Magnetic Resonance Society
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    • v.19 no.2
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    • pp.88-94
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    • 2015
  • Bub1 is one of the spindle checkpoint proteins and plays a role in recruitment of the related proteins to kinetochore. Here, we studied the structural characteristic of the evolutionarily conserved 160 amino acid region in the N-terminus (hBub1 CD1), using Circular Dichroism (CD) and NMR. Our CD results showed that hBub1 CD1 is a highly helical protein and its structure was affected by pH: as pH was elevated to basic pH, the helical propensity increased. This could be related to the surface charge of the hBub1 CD1. However, the structural change did not largely depend on the salt concentration, though the thermal stability a little increased. The previous NMR analysis revealed that the hBub1 CD1 adopts eight helices, which is consistent with the CD result. Our result would be helpful for evaluating the molecular mechanism of the hBub1 CD1 and protein-protein interactions.

Protein Adsorption and Hydrodynamic Stability of a Dense, Pellicular Adsorbent in High-Biomass Expanded Bed Chromatography

  • Chow, Yen Mei;Tey, Beng Ti;Ibrahim, Mohd Nordin;Ariff, Arbakariya;Ling, Tae Chuan
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.11 no.3
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    • pp.268-272
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    • 2006
  • A dense, pellicular UpFront adsorbent ($p=1.5 g/cm^3$, UpFront Chromatography, Cophenhagen, Denmark) was characterized in terms of hydrodynamic properties and protein adsorption performance in expanded bed chromatography. Cibacron Blue 3GA was immobilised into the adsorbent and protein adsorption of bovine serum albumin (BSA) was selected to test the setup. The Bodenstein number and axial dispersion coefficient estimated for this dense pellicular adsorbent was 54 and $1.63{\times}10^{-5}m^2/s$, respectively, indicating a stable expanded bed. It could be shown that the BSA protein was captured by the adsorbent in the presence of 30% (w/v) of whole-yeast cells with an estimated dynamic binding capacity $(C/C_o = 0.01)$ of approximately 6.5 mg/mL adsorbent.

Effects of Light on Disassembly of Chloroplast during Senescence of Detached Leaves in Phaseolus vulgaris

  • Lee Dong-Hee;Hong Jung-Hee;Kim Young-Sang
    • Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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    • v.1 no.2
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    • pp.69-80
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    • 1997
  • Effects of light on leaf senescence of Phaseolus vulgaris were investigated by measuring the disassembly of chlorophyll-protein complexes in detached leaves which had been kept in the dark or under light. The loss of chlorophyll accompanied by degradation of chlorophyll-protein complexes. PSI (photosystem I) complex containing LHCI (light harvesting complex of PSI) apoproteins was rapidly decreased after the early stage of dark-induced senescence. RC(reaction center)-Core3 was slightly increased until 4 d and slowly decreased thereafter. As disassembly of LHCII trimer progressed after the late stage of senescence, there was a steady increase in the relative amount of SC(small complex)-2 containing LHCII monomer. On the other hand, white and red light adaptation caused the structural stability of chlorophyll-protein complexes during dark-induced senescence. Particularly, red light was more effective in the retardation of LHCII breakdown than white light, whereas white light was slightly effect in protecting the disassembly of PSI complex compared to red light. These results suggest, therefore, that light may be a regulatory factor for stability of chlorophyll-protein complexes in the senescent leaves.

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Protein Cyclization Enhanced Thermostability and Exopeptidase-Resistance of Green Fluorescent Protein

  • Zhao, Zhonglin;Ma, Xin;Li, Liang;Zhang, Wei;Ping, Shuzhen;Xu, Ming-Qun;Lin, Min
    • Journal of Microbiology and Biotechnology
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    • v.20 no.3
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    • pp.460-466
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    • 2010
  • A mutant of green fluorescent protein ($GFPmut3^*$) from the jellyfish Aequorea victoria was cyclized in vitro and in vivo by the use of a naturally split intein from the dnaE gene of Synechocystis species PCC6803 (Ssp). Cyclization of $GFPmut3^*$ was confirmed by amino acid sequencing and resulted in an increased electrophoretic mobility compared with the linear $GFPmut3^*$. The circular $GFPmut3^*$ was $5^{\circ}C$ more thermostable than the linear form and significantly more resistant to proteolysis of exopeptidase. The circular $GFPmut3^*$ also displayed increased relative fluorescence intensity. In addition, chemical stability of $GFPmut3^*$ against GdnHCl revealed more stability of the circular form compared with the linear form.

Cyclic AMP Receptor Protein Adopts the Highly Stable Conformation at Millimolar cAMP Concentration (높은 cAMP 농도에서 cAMP 수용성 단백질의 열 안정화)

  • Kang, Jong-Baek;Choi, Young
    • Journal of Life Science
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    • v.13 no.5
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    • pp.751-755
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    • 2003
  • Cyclic AMP receptor proteins(CRP) activate many genes in Escherichia coli by binding of cAMP with not fully known mechanism. CRP existed as apo-CRP in the absence of cAMP, $CRP;(cAMP)_2$$_2$ at low(micromolar) cAMP concentration, or $CRP;(cAMP)_4$ at high(millimolar) concentration of cAMP. This study is designed to measure the thermal stability of S83G CRP, which substituted glycine for serine at amino acid 83 position, with CD spectrapolarimeter at 222nm by the constant elevation of temperature from $20^{\circ]C\; to\; 90^{\circ}C\; at\; 1^{\circ}C/min$. The non-linear regression analysis showed that melting temperatures were 68.4, 72.0, and $82.3^{\circ}C$ for no cAMP, 0.1mM cAMP, and 5mM cAMP, respectively. Result showed the strong thermal stability of CRP by binding of additional cAMP molecules to region between the hinge region and helix-turn-helix(HTH) motif at 5mM cAMP concentration.

Effect of Phosphate and Citrate Salts on the Emulsion Stability of Soy Protein Isolate in the Presence of Calcium (칼슘 존재하에서 인산과 구연산업이 분리대두단백질의 유화 안정성에 미치는 영향)

  • Kim, Yeong-Suk;Yeom, Dong-Min;Hwang, Jae-Gwan
    • The Korean Journal of Food And Nutrition
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    • v.7 no.3
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    • pp.177-182
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    • 1994
  • The effect of phosphate salt (NafHP04) and sodium citrate on the emulsion stability of soy protein isolate (SPI) in the presence of calcium was investigated in terms of salt concentration and addition order. Both phosphate and citrate salts decreased the solubility of SPI despite their pH enhancing effects. Addition of calcium chloride (CaCl2) significantly decreased ES, which showed nearly negligible at more than 3 mM CaCl2 concentration. When Na2HP04 were added in the presence of 5 mM Cac12, 55 greatly increased up to 20mM concentration, above which however ES decreased. It was found that the addition order of Na2HPO4 and CaCl2 affected ES. The addition of phosphate and subsequent CaCl2 exhibited the higher 55 than the reverse order. In both cases, the overall ES profile was found to be nearly similar to the solubility profile of SPI, indicating the positive relationship between solubility and emulsion stability of SPI in the presence of calcium. Similar trend to the phosphate effect on ES was also observed for sodium citrate in the presence of calcium.

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Processing, Quality Stability and Utilization of Approved Sardine Surimi for Surimi-based Products (정어리 개량고기풀의 제조와 품질 안정성 및 이용성)

  • 김태진;서상복;이두석;민진기
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.28 no.2
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    • pp.403-408
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    • 1999
  • This study was conducted to investigate chemical properties, quality stability and utilization of approved sardine surimi(ASS) which is developed our laboratory. The product yield of the ASS was about 3 times higher than that of usual sardine surimi(SS). The proper addition concentration of sodium bicarbonate was 0.1% for the neutralization of the ASS. The content of salt soluble protein nitrogen in the ASS was about the half of that in the SS, while the content of water soluble protein nitrogen was 2.4 times higher in ASS. The total amount of free amino acids in the ASS was about 11 times higher than that of the SS. Predominant free amino acids in the ASS were histidine, taurine, glutamic acid and alanine, and those four amino acids occupied 94% of total amount of free amino acids. During cold storage at 21oC for 6 months, the quality of ASS was more stable than that of SS in judging from changes of water soluble and salt soluble protein nitrogen, AV and POV. Quality of fish burger, fish sausage and fried fish paste processed in accordance with commercial processing preparation using the ASS or SS exclusively and mixtures which other white meat fish surimi(alaska pollack, hair tail and sole) were proportionallly added to each of two types of sardine meat were evaluated. In case of fish burger, the product processed from the ASS only were superior.

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Effect of phosphate salts on the emulsion stability of soy protein isolate (분리 대두 단백질의 유화 안정성에 관한 인산염의 영향)

  • Hwang, Jae-Kwan;Kim, Young-Sook;Pyun, Yu-Ryang
    • Applied Biological Chemistry
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    • v.35 no.3
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    • pp.152-156
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    • 1992
  • A study was condoled to investigate the effects of phosphate salts $(Na_2HPO_4\;and\;K_2HPO_4)$ on the emulsion stability of soy protein isolate (SPI) in terms of the salts concentration and addition order. When phosphates were added before emulsification, emulsion stability (ES) of SPI was improved at the concentration of 10 mM, while ES was decreased by addition of phosphates after emulsification. At high phosphate concentrations, ES of SPI was decreased by the addition of phosphates, regardless of the addition order. ES of SPI at the isoelectric point (pH 4.5) or in the presence of $CaCl_2$ was greatly enhanced by the phosphates. In both cases, the overall ES profile was found to be nearly similar to the solubility profile of SPI, indicating the positive relationship between solutibility and emulsion stability of SPI.

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