• Title/Summary/Keyword: Protein coprecipitation

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Coprecipitation Characteristics of Cheese Whey and Soybean Proteins (유청(乳淸)과 대두 단백질(蛋白質)의 공동침전(共同沈殿) 특성(特性))

  • Wee, Jae-Joon;Lee, Hyong-Joo
    • Applied Biological Chemistry
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    • v.26 no.4
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    • pp.199-204
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    • 1983
  • As a way of utilizing cheese whey to fortify sulfur-bearing amino acids to soybean protein, whey-soybean coagulum was made from whey-soy milk mixture and optimum conditions for coprecipitation of the two proteins were determined. Mixture of whey and soymilk in 1 : 1 volume ratio was coagulated at $0.005{\sim}0.5M$ of $CaCl_2$ concentration, pH $1.5{\sim}8.0$, and at $60{\sim}100^{\circ}C$, and absorbance at 500nm of filtrate from the coagulum was measured. Optimum conditions for the coprecipitation were 0.0125M of $CaCl_2$ concentration, pH $6.5\sim7.5$, and $70{\sim}80^{\circ}C$ which resulted in the minimum absorbance and also good physical properties of the curd.

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Association of Killer Cell Ig-like Receptor (KIR) with an Adaptor Protein Shc

  • Cho, Hyun-Il;Chwae, Yong-Joon;Park, Sang-Myun;Kim, Jong-Sun
    • IMMUNE NETWORK
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    • v.6 no.2
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    • pp.67-75
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    • 2006
  • Background: Cytotoxic function of killer cells is inhibited by specific recognition of class I MHC molecules on target cells by inhibitory killer Ig-like receptors (KIR) expressed on NK cells and some cytotoxic T cells. The inhibitory effect of KIR is accomplished by recruitment of SH2-containing protein tyrosine phosphatase (SHP) to the phosphotyrosine residues in the cytoplasmic tail. Methods: By in vitro coprecipitation experiments and transfection analysis, we investigated the association of KIR with an adaptor protein Shc in Jurkat T cells. Results: The cytoplasmic tail of KIR appeared to associate with an adaptor protein Shc in Jurkat T celilysates. Similar in vitro experiments showed that phosphorylated KIR cytoplasmic tail bound SHP-1 and Shc in Jurkat T cell lysates. The association of KIR with Shc was further confirmed by transfection analysis in 293T cells. Interestingly, however, Shc appeared to be replaced by SHP-2 upon engagement of KIR in 293T cells. Conclusion: Our data indicate that KIR associate with an adaptor protein Shc in Jurkat T cells, and suggest that KIR might have an additional role which is mediated by this adaptor protein.

Effect of Coagulants on the Quality of Soybean Curd Added With Cow's Milk (응고제가 우유 첨가 두부의 품질에 미치는 영향)

  • Kim, Tae-Young;Kim, Joong-Man;Cho, Nam-Jun
    • Applied Biological Chemistry
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    • v.37 no.5
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    • pp.370-378
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    • 1994
  • Soybean curd added with 40% of cow’s milk was prepared with eight coagulants such as calcium acetate, calcium lactate, calcium chloride, calcium sulfate, magnesium chloride, glucono-delta lactone (GDL), acetic acid and lactic acid. The curd products were evaluated by the chemical composition, coprecipitation porperties, mineral content, yield, color and textural characteristics. The lowest concentrations for protein coprepitation were 0.3% (v/v) for calcium salts, 0.4% (v/v) for magnesium chloride, 0.2% (v/v) for organic acids. Turbidity and crude protein of whey were markedly decreased at these concentrations. The optimal concentrations of coagualnts used for soybean curd preperation were 1.2% (v/v) for calcium acetate, calcium sulfate and calcium lactate, 1.0% (v/v) for calcium chloride and GDL, 0.8% (v/v) for magnesium chloride and lactic acid, 0.6% (v/v) for acetic acid. It was observed that of the eight coagulants tested, calcium chloride provided a satisfactory curd in quality. Calcium content of soybean curds by the calcium salt coagulants was higher than that by organic acid coagulants. Through the examination on the textural properties by a texturemeter was found out that acetic acid treated soybean curd among the organic acids, calcium salts and magnesium chloride treated curds had very high hardness value. All the curd products prepared in this experiment had a pale yellow color as affected by the value of L (lightness), a (redness) and b (yellowness). Although the colorimetric readings showed that the soybean curds prepared with the organic acids had higher L value but lower a and b value in comparison to calcium salts and magnesium chloride treated curds.

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Functionalization of Fe3O4 Nanoparticles and Improvement of Dispersion Stability for Seperation of Biomolecules (생체분자 분리를 위한 Fe3O4 나노입자의 표면수식과 분산 안정성 향상)

  • Kim, Min-Jung;An, Guk-Hwan;Lim, Borami;Kim, Hee-Taik;Choa, Yong-Ho
    • Journal of Powder Materials
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    • v.14 no.4
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    • pp.256-260
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    • 2007
  • The surface of magnetite ($Fe_{3}O_{4}$) nanoparticles prepared by coprecipitation method was modified by carboxylic acid group of poly(3-thiophenacetic acid (3TA)) and meso-2,3-dimercaptosuccinic acid (DMSA). Then the lysozyme protein was immobilized on the carboxylic acid group of the modification of the magnetite nanoparticles. The magnetite nanoparticles are spherical and the particle size is approximately 10 nm. We measured quantitative dispersion state by dispersion stability analyzer for each $Fe_{3}O_{4}$ nanoparticles with and without surface modification. The concentration of lysozyme on the modified magnetite nanoparticles was also investigated by a UV-Vis spectrometer and compared to that of magnetite nanoparticles without surface modification. The functionalized magnetite particles had higher enzymatic capacity and dispersion stability than non-functionalized magnetite nanoparticles.

Characteristics of Cheese Manufactured by Coprecipitation of Whey and Soy Milk (유청 및 두유의 공동침전에 의해 제조된 치즈의 특성)

  • Kim, Jeong-Hwan;Lee, Hyong-Joo
    • Korean Journal of Food Science and Technology
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    • v.17 no.3
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    • pp.213-218
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    • 1985
  • As a way of improving the texture and flavor of soybean cheese, whey-say cheeses were made by coprecipitation of various mixtures of whey, whey powder, soy milk and soy protein powder, and mixed culture of str. lactis, str. cremoris and rennet were added, then the cheeses were cured at $15^{\circ}C$ for up to 10 weeks. Physicochemical characteristics of the cheese were investigated by analyzing pH, titratable acidity(TA), water soluble nitrogen, 10% TCA soluble nitrogen, amino acid composition, beany flavor, color and hardness. The pH of whey-soy cheeses during ripening changed from 5.3 to 4.2 after 5 or 6 weeks and maintained that value while that of soybean cheese maintained a higher pH value. TA of whey-soy milk cheeses was gradually increased to the value of 0.4-0.45 after 8 weeks, but that of soybean cheese reached only 0.2 after the same period. Water soluble and 10% TCA soluble-nitrogen increased steadily during ripening. Hardness of the whey-soy milk cheeses reached maximum after three weeks of ripening and greatest at those made from 3 : 1 mixture of whey and soy milk and that from soymilk. Color of the whey-soy milk chesses was lighter than that of soybean cheese. The bean flavor of soybean cheese was strong and persistent for the whole ripening period. Acid flavor was dominant in the whey-so milk cheese and masked the beany flavor partially.

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Characteristics of Amino Acid Fortified Tofu Manufactured by Coprecipitation of Whey and Soybean Proteins (유청(乳淸)과 대두(大豆) 단백질(蛋白質) 공동침전(共同沈澱)에 의해 제조(製造)된 아미노산 강화두부(强化豆腐)의 특성(特性))

  • Wee, Jae-Joon;Lee, Hyong-Joo
    • Applied Biological Chemistry
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    • v.26 no.4
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    • pp.205-210
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    • 1983
  • To investigate the characteristics of amino acid fortified tofu manufactured by coprecipition of cheese whey and soybean proteins, experimental tofus were made from various mixtures of whey, whey powder, and soy milk, and general and amino acid compositions and physical properties were analyzed. Physical characteristics such as elasticity, hardness, and brittleness of the whey-soybean tofu were very similar to those of traditional tofu but color of the whey-soybean tofu was lighter than that of soybean tofu. The contents of total solids and protein of traditional tofu were about 19% and 13%, respectively, while those of the whey-soy bean tofus were 17.3%$\sim$18.1% and 10.9$\sim$11.3%, respectively. The 5$\sim$15% of lactose in whey-soymilk mixture was transferred into the tofus. The Content of sulfur-bearing amino acids in the fortified tofu from 3 : 1 mixture of whey and soymilk was 3.8g/100g protein which indicated about 50% fortification of the amino acids as compared to the traditional tofu which contained 2. 54g/100g protein of the sulfur-bearing amino acids.

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