• Korean Journal of Poultry Science
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• v.29 no.1
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• pp.45-52
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• 2002

Cryoprotective effects on chicken surimi during storage were investigated. Chicken surimi from mechanically deboned spent layer meat was prepared with 4 volumes of 0.5% NaCl washing, and then blended with or without cryoprotectants (8% trehalose, 8% oligosaccharide) prior to frozen storage at $-18^{\circ}C$ to 10 weeks Redness (a) of all surimi decreased during storage. Color stability increased during storage when lightness increased but redness decreased. At this Point, surimi maintained a better color quality as followed order; trehalose > oligosaccharide ) non-additive. Gel strength such as compressive force, hardness, adhesiveness and gumminess tended to decrease during frozen storage. Cryoprotectants provided significantly better textural properties than non-auditive. Surimi with trehalose showed the highest adhesiveness. In conclusion, trehalose and oligosaccharide seemed to be good cryoprotectants of chicken surimi. Especially, trehalose resulted in better cryoprotectant than oligosaccharide because of better color stability, better textural properties, and lower sweet characteristics.

• Journal of Life Science
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• v.10 no.3
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• pp.279-285
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• 2000

CRP (cyclic AMP receptor protein) regulate transcription of catabolite-sensitive genes in Escherichia coli. Wild-type and mutant CRP (S83G and S128A) proteins were used to measure the thermal stability and the temperature-dependent structural change by proteolytic digestion, UV spectrophotometer and CD spectrapolarimeter. The result indicated that wild-type CRP was more thermally stable than the mutant CRPs in the presence of cAMP. At a low temperature, wild-type CRP with cAMP was more sensitive to subtilisin than the mutant CRPs. At a high temperature, there was no difference of sensitivity to subtilisin among wild-type, S83G and S128A CRPs. CD spectra suggested that the secondary structure of CRP was destroyed partially at a high temperature.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2005.05a
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• pp.226-230
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• 2005

본 연구는 고혈압을 억제하는 ACE inhibitory peptide가 한우에 함유되어 있는지를 조사하기 위한 기초연구로 한우의 우둔과 등심으로부터 Myosin B를 추출하여 가열한 것과 가열하지 않은 것으로 구분하여 pepsin으로 0, 1, 3, 6시간 동안 $37^{\circ}C$에서 가수분해 시켰다. 가수분해물을 전기영동을 실시하여 pepsin 처리시간에 따른 단백질의 변화를 검토하였고, ACE 저해 활성을 측정하였다. 전기영동의 결과 가열한 것은 가열하지 않은 것에 비해서 단백질의 변성과 소멸이 많이 일어나 밴드의 수가 적었다. Pepsin으로 가수분해한 시간이 길어짐에 일부 단백질이 소실되었고, 저분자의 단백질이 생성되었다. Pepsin으로 가수분해함에 따라 등심과 우둔에서 25, 32, 40 및 44 kDa는 소실되었고, 37 kDa의 분자량을 갖는 밴드는 생성되었으며, 27 kDa의 단백질은 처음상태 그대로 유지되었다. 가수분해물을 이용하여 ACE 저해활성도를 측정한 결과, 등심은 1시간 가수분해시 유의차가 있었으나, 우둔은 가열여부에 따라 유의차가 발견되지 않았다. 반면 등심과 우둔 모두 가수분해 시간이 증가하면 ACE 저해율은 상승하는 경향을 보였다. 이와 같은 결과를 토대로 한우로부터 추출한 Myosin B의 ACE 억제활성이 우수한 단백질분획을 찾아 아미노산 염기서열을 밝히고 고혈압 억제제로 합성 개발하는 연구를 차후 추진할 예정이다.

• Journal of Life Science
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• v.8 no.2
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• pp.223-233
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• 1998

Discovery of molecular chaperone has stimulate cell biologists and thus made it possible to re-examine the processes whereby proteins achieve and maintain their functional conformations within living cells. the term ‘Molecular chaperone’ was first coined to describe one particular protein involved in the assembly of nucleosomes, but the term has now been extended to describe the function of a wide variety of proteins that assist protein transport across membranes, folding of nascent polypeptide, the assembly and disassembly of oligomeric structures, and the recovery or removal of proteins damaged by various environmental stresses including heat shock. Progress of molecular chaperone research is still limited by the lack of 3-dimensional structural information and detailed interacts with taget proteins in the cell. However, several laboratories around the world are attempting to extend our knowledge on the functions of molecular chaperone, and such efforts seem justified to finally provide the answers to the most burning questions shortly.

• Journal of the Korean Chemical Society
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• v.52 no.1
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• pp.57-65
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• 2008

are nanometer or micrometer scale vesicles that can be used as drug delivery carriers. However, plain liposomes are plagued by rapid opsonization, making their circulation time in bloodstream be shortened. In this study, model protein, bovine serum albumin (BSA)-coated liposomes were prepared by coating cationic liposomes with BSA molecules at higher pH than isoelectric point of BSA. The BSA molecules coated on the liposomal surface were denatured by thermal treatment at above 60oC. While both plain and cationic liposomes had about mean particle diameter of 1041 nm, BSA-coated cationic liposomes (BCL) had mean particle diameter of 1091 nm. Encapsulation of model drug, doxorubicin (DOX), in liposomes were carried out by using remote loading method and the loading efficiency of DOX to liposomes was about 90%. The mean particle diameter of BCL did not increase in blood plasma and adsorption of plasma protein was much less than plain or cationic liposomes. These results suggest that BCL can be used as a long-circulating liposomes in bloodstream.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.6
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• pp.823-828
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• 1998

The objective of this study is to investigate cryoprotective effects of corn starch enzyme hydrolysates of nonsweet and low-calories on denaturation of frozen fish protein. The cryoprotective effects of were examined in Alaska pollack actomyosin solution by changes in SDS-PAGE pattern, solubility, and $Ca^{2+}$-ATPase activity. When samples stored for 0 and 30 days were compared on SDS-PAGE patterns, severe changes in all bands were shown on the control sample regardless of storage temperature, especially in myosin heavy chain (MHC). Not much difference no appeared the electrophoretic pattern in case of the samples containing sucrose at any storage temperature during 30 days of storage. The cryoprotective effect of the hydrolysates were markedly dependant on storage temperature and no MHC band was found in the samples stored at $-5^{\circ}C$. The SDS-PAGE patterns of sample stored at $-20^{\circ}C$, however, completely maintained after 30 days or storage. When the samples were stored at $-5^{\circ}C$, the solubility of the sample containing sucrose was retained at $90\%$ after 30 days of storage, whereas dramatically decreased in other samples. The samples including sucrose, D.E. 10, 15, and 20 revealed $90\%$ in solubility when stored at $-20^{\circ}C$. The tendency of remaining $Ca^{2+}$-ATPase activity was almost shown the same as that of solubility.

• Journal of Life Science
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• v.9 no.6
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• pp.733-736
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• 1999

The doubly altered mutant tryptophan synthase $\alpha$-subunits, in which Thr 24 was replaced by Ser, Leu or Lys in addition to F139W substitution, were purified. Urea-induced unfolding equilibrium curves of these proteins, monitored by fluorescence intensity of tryptophan, show that the alterations of residue 24 resulted in marked changes in folding properites, suggesting the importance of this residue in folding of this protein.

• Food Science of Animal Resources
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• v.22 no.2
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• pp.179-182
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• 2002

Using differential scanning calorimetry (DSC), changes underwent by a mixture of $\alpha$-lactalbumin ($\alpha$-La) and $\beta$-lactoglobulin ($\beta$-Lg) during heat treatment were studied, yielding useful information for the dairy industry. Results of the DSC showed that the heat denaturation temperature of the hobo-$\alpha$-La was higher than that of apo-$\alpha$-La, suggesting hole-$\alpha$-La‘s greater stability. The denaturation temperature of a mixture of holo-$\alpha$-La and $\beta$-Lg was also slightly lower than that of holo-$\alpha$-La alone. The denaturation temperature of an apo-$\alpha$-La and $\beta$-Lg mixture was higher than that of holo-$\alpha$-La and $\beta$-Lg, suggesting that the heat stability of apo-$\alpha$-La was increased by $\beta$-Lg. Based on these results, it is possible to conclude that a mixture of holo-$\alpha$-La and $\beta$-Lg is more intensively affected by an increase in temperature than other samples, and that free sulphydryl groups seem to take part in this heat-induced denaturation.

• Bulletin of Food Technology
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• v.9 no.2
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• pp.133-139
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• 1996

최근 6할이상의 주부들이 가공식품 혹은 반가공식품을 이용하고 있으며 그 이유는 이용의 간편성, 조리가 간단하고 합리지향적인 구매행위가 가능한 점으로 꼽을 수 있다. 특히, 일본의 경우 노년인구층의 급증으로 인한 부드러운 식품소재의 이용성이 크게 늘어나고 있는 추세에서, 강하지않고 부드러운 향미 및 질감, 먹기쉬운 간편성등과 영양기능성이 강조된 제품개발이 활발히 이루어지고 있다. 따라서, 가공식품을 개발하려는 목적위에 소비자의 연령층에 대응하고, 보다 고도의 기능특성(영양성, 안전성, 경제성등)을 결합시킨 개념들이 도입되고 있다. 단백질은 가공식품의 물성을 결정하는 성분으로써 우유, 계란, 대두 및 밀가루단백질들을 이용하여 물성개량을 위한 잠정적 식품첨가물로 이용가치가 높다. 주로 구상단백질로 구성이 되어 있는 우유의 유청단백질을 특수한 처리에 의해 가용성 선상응집체(Soluble linear aggregate)로 가공한 유청단백질(Process whey protein)은 원래의 미변성 유청단백질에 비해 증강된 기능특성(표 1)을 지니고 있다. 지난 10년간 유청의 유용성에 대한 인식이 증가된 것은 물론 막기술이나, 이온 교환기술을 이용한 유청가공기술이 점진적으로 발달해왔다. 유청의 원재료는 물론이고 가공적성을 이해함으로써, 산 안전성, 겔화, 막형성, 기포형성, 유화액형성 등의 수많은 식품학적 기능특성들이 제고될 수 있다. 따라서, 식품에 응용될 수 있는 이들 기능특성들을 다듬어, 유청단백질을 특별한 목적용 제품으로 개발할 수 있도록 넓은 범위의 정보를 제공하는 것이 중요하다. 이에 유청단백질의 제조 및 가공을 제고하고, 식품에 광범위하게 응용할 수 있는 유청단백질의 다양한 식품학적 기능특성을 논의하고자 한다.

• Food Science of Animal Resources
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• v.25 no.2
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• pp.232-237
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• 2005

Lactoferrin is a member of the transferrin family of iron-binding glycoproteins. It is originally found in milk. In addition to its antibacterial and antiviral activities, lactoferrin has many other biological functions include anti-inflammatory properties, antitumor, cell growth-promoting activity as well as antioxidant effect In the present study, we report the production of recombinant bovine lactoferrin and lactoferrin N-lobe in the Rhodococcus erythropolis (R erythropolis) using pTip vector. The expression level was investigated in various range of temperature, and we could successfully expressed the bovine lactoferrin and lactoferrin N-lobe in R erythropolis at low temperature. The recombinant proteins were purified by Nickel-Nitrolotriacetic acid (Ni-NTA). The purified proteins were confirmed by SDS-PAGE and Western blot, which indicating that the recombinant proteins have a molecular weight of 80kDa and 43kDa for bovine lactoferrin and lactoferrin N-lobe, respectively.