• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.21-21
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• 2011

A series of Quasi-Elastic Neutron Scattering (QENS) experiments helps us to understand the single-particle (hydrogen atom) dynamics of a globular protein and its hydration water and strong coupling between them. We also performed Molecular Dynamics (MD) simulations on a realistic model of the hydrated hen-egg Lysozyme powder having two proteins in the periodic box. We found the existence of a Fragile-to-Strong dynamic Crossover (FSC) phenomenon in hydration water around a protein occurring at TL=$225{\pm}5K$ by analyzing Intermediate Scattering Function (ISF). On lowering of the temperature toward FSC, the structure of hydration water makes a transition from predominantly the High Density Liquid (HDL) form, a more fluid state, to predominantly the Low Density Liquid (LDL) form, a less fluid state, derived from the existence of a liquid?liquid critical point at an elevated pressure. We showed experimentally and confirmed theoretically that this sudden switch in the mobility of the hydration water around a protein triggers the dynamic transition (so-called glass transition) of the protein, at a temperature TD=220 K. Mean Square Displacement (MSD) is the important factor to show that the FSC is the key to the strong coupling between a protein and its hydration water by suggesting TL${\fallingdotseq}$TD. MD simulations with TIP4P force field for water were performed to understand hydration level dependency of the FSC temperature. We added water molecules to increase hydration level of the protein hydration water, from 0.30, 0.45, 0.60 and 1.00 (1.00 is the bulk water). These confirm the existence of the FSC and the hydration level dependence of the FSC temperature: FSC temperature is decreased upon increasing hydration level. We compared the hydration water around Lysozyme, B-DNA and RNA. Similarity among those suggests that the FSC and this coupling be universal for globular proteins, biopolymers.

• 한국축산식품학회지
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• 제18권1호
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• pp.35-41
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• 1998

The objective of this study was to examine the changes of physical properties by additions of different kinds of stabilizers milk proteins concentration, when stored at 4$^{\circ}C$ or 20$^{\circ}C$ for yoghurt. the results were summarized as follows: 1. Addition of 2% carboxyl methyl cellulose and carrageenan, gelation 0.4%, pectin and starch 0.6%, and carrageenan & pectin 0.8% in the manufacture of yoghurt increased the viscosity, water-holding capacity and protein hydration of yoghurt. 2. Addition of 3% skim milk powder, Ca-caseinate or Na-caseinate 0.6% increased the viscosity, water-holding capacity and protein hydration of yoghurt. 3. Twenty five percent of evaporation of milk promoted to build up the optimal structure of the micelles of yoghurt and improved viscosity, water-holding capacity and protein hydration of yoghurt. 4. Addition of stabilizers to yoghurt showed an increase of viscosity, water-holding capacity and protein hydration when compared with non-addition of stabilizers to yoghurt at 4$^{\circ}C$, 20$^{\circ}C$ storage for 12hrs, 96hrs followed by the decrease of it.

• EDISON SW 활용 경진대회 논문집
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• 제3회(2014년)
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• pp.103-113
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• 2014

Hydrophobicity is the key concept to understand the role of water in protein folding, protein self-assembly, and protein-ligand interaction. Conventionally, hydrophobicity of amino acids in a protein has been argued based on hydrophobicity scales determined for individual free amino acids, assuming that those scales are unaltered when amino acids are embedded in a protein. Here, we investigate how the hydrophobicity of constituent amino acids depends on the protein context, in particular, on the total charge and secondary structures of a protein. To this end, we compute and analyze the hydration free energy - free energy change upon hydration quantifying the hydrophobicity - of three short proteins based on the integral-equation theory of liquids. We find that the hydration free energy of charged amino acids is significantly affected by the protein total charge and exhibits contrasting behavior depending on the protein net charge being positive or negative. We also observe that amino acids in the central ${\beta}$-strand sandwiched by ${\beta}$-sheets display more enhanced hydrophobicity than free amino acids, whereas those in the ${\alpha}$-helix do not clearly show such a tendency. Our results provide novel insights into the hydrophobicity of amino acids, and will be valuable for rationalizing and predicting the strength of water-mediated interaction involved in the biological activity of proteins.

• EDISON SW 활용 경진대회 논문집
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• 제5회(2016년)
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• pp.163-166
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• 2016

Hydrophobicity is the key concept to understand the water plays in protein folding, protein aggregation, and protein-protein interaction. Traditionally, the hydrophobicity of protein is defined based on the scales of the hydrophobicity of residue, assuming that the hydrophobicity of free amino acids is maintained. Here, we explore how the hydrophobicity of constituting amino acids in protein rely on the protein context, in particular, on the total charge and secondary structures of a protein. To this end, we calculate and investigate the hydration free energy of three short proteins based on the integral-equation theory of liquids. We find that the hydration free energy of charged amino acids is significantly affected by the protein total charge and exhibits contrasting behavior depending on the protein total charge being positive or negative. We also observe that amino acids in the ${\beta}-sheets$ display more enhanced the hydrophobicity than amino acids in the loop, whereas those in the ${\alpha}-helix$ do not clearly show such a tendency. And the salt-bridge forming amino acids also exhibit increase of the hydrophobicity than that with no salt bridge. Our results provide novel insights into the hydrophobicity of amino acids, and will be valuable for rationalizing and predicting the strength of water-mediated interaction involved in the biological activity of proteins.

• 한국수산과학회지
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• 제35권6호
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• pp.627-632
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• 2002

[ $10\%$ ]의 단백질농도에서 5, 15, 25, 35$^{\circ}C$에서 각각 48시간까지 수화시킨 첨가단백질의 겔 형성능을 조사하였을 때 대두단백이 혈장단백, 건조난백과 같은 다른 2가지 첨가단백질 사이에는 중요한 차이가 있었으며, 이는 대두단백은 모든 조건에서 겔을 형성하지 못하였고, 수화는 5$^{\circ}C$, 12시간 24시간에서 혈장단백의 젤리강도를 $10\%$ 정도 상승시켰으며, 건조난백의 경우 5, 15, 25$^{\circ}C$에서 12, 24시간에서 $60\%$ 정도 젤리강도를 증가시켰다. 이와 같이 겔 형성능이 상승한 경우는 수화가 단백질의 인력과 척력의 적절한 균형을 제공한 것으로 추정되며, 실제 단백질의 겔 형성능을 이용하는 많은 식품이 있고 또한 가공공정이 다양하지만 적절한 수화공정의 추가는 겔 형성능을 상승시킬 수 있을 것으로 판단되었다.

• 대한화장품학회지
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• 제42권4호
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• pp.343-349
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• 2016

제주용암해수는 미네랄과 영양염류가 풍부한 물로 제주만이 보유한 지하수자원이다. 본 연구의 목적은 제주용암해수의 피부 보습효과를 확인하기 위한 것이다. 피부의 건조함을 막고 수분을 유지하기 위해서는 표피층의 장벽기능이 정상적으로 기능하고, 표피층 내 수분의 유지와 이동이 원활히 이루어져야 한다. 제주용암해수를 각질형성세포에 처리한 결과 표피층의 분화과정과 natural moisturizing factor (NMF) 생성과정에 관여하는 유전자인 필라그린과 caspase-14 유전자의 발현양이 증가되는 것을 확인할 수 있었다. 또한 막관통 단백질로 수분의 이동을 조절하는 aquaporin 3 (AQP3) 유전자 발현양과 단백질 발현양도 제주용암해수 처리에 의해 증가하였다. 인공피부를 이용한 실험에서 제주용암해수를 배지에 처리하고 배양한 결과 hyaluronic acid (HA)의 수용체인 CD44의 발현양이 증가하였다. 본 연구를 통해 제주용암해수는 피부 보습과 관련된 인자들의 발현양을 증가시켜 피부의 보습기능에 도움을 주는 것으로 사료되었다.

• Applied Biological Chemistry
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• 제28권2호
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• pp.62-67
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• 1985

일반계(35 품종) 및 다수계(24 품종) 쌀의 수분 흡수 속도에 미치는 인자에 대하여 조사하였다. 각 품종마다 독특한 수분 흡수 속도를 보였으나, 대체로 다수계 품종이 일반계 품종에 비하여 수분 흡수 속도가 빨랐다. 쌀의 수분 흡수 속도는 단백질, 아밀로스, 쌀알의 표면적 및 부피와 상관 관계를 보이지 않았으나, 쌀알의 길이와 폭의 비와는 부의 상관을 보였다.

• Preventive Nutrition and Food Science
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• 제20권1호
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• pp.15-21
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• 2015

The skin plays a key role in protecting the body from the environment and from water loss. Cornified envelope (CE) and natural moisturizing factor (NMF) are considered as the primary regulators of skin hydration and barrier function. The CE prevents loss of water from the body and is formed by cross-linking of several proteins. Among these proteins, filaggrin is an important protein because NMF is produced by the degradation of filaggrin. Proteases, including matriptase and prostasin, stimulate the generation of filaggrin from profilaggrin and caspase-14 plays a role in the degradation of filaggrin. This study elucidated the effects of an ethanol extract of Boesenbergia pandurata (Roxb.) Schltr., known as fingerroot, and its active compound panduratin A on CE formation and filaggrin processing in HaCaT, human epidermal keratinocytes. B. pandurata extract (BPE) and panduratin A significantly stimulated not only CE formation but also the expression of CE proteins, such as loricrin, involucrin, and transglutaminase, which were associated with $PPAR{\alpha}$ expression. The mRNA and protein levels of filaggrin and filaggrin-related enzymes, such as matriptase, prostasin, and caspase-14 were also up-regulated by BPE and panduratin A treatment. These results suggest that BPE and panduratin A are potential nutraceuticals which can enhance skin hydration and barrier function based on their CE formation and filaggrin processing.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1286-1286
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• 2001

Despite extensive theoretical and experimental studies the structure of the protein-solvent interface is subject of many controversy. Understanding the processes that occur in aqueous solution requires understanding of the solvent influence on the structure of protein. The aim of this study is to investigate the applicability of NIR methods in the study of hydration phenomena in protein solutions. Temperature-induced changes in NIR spectra of -lactoglobulin (BLG) in aqueous solutions have been investigated by means of two-dimensional correlation spectroscopy (2DCOS) and principal component analysis (PCA). With the temperature increase the balance of forces between the BLG's interaction with itself and the BLGs interaction with its environment is disrupted leading to BLG unfolding. Significant differences of 2D signals and distinct discrepancies of loading on PC1 and PC2 were observed as a result of temperature increase. In the native folded conformation of BLC, most of the nonpolar amino acids are hidden in the centre of the structure, out of contact with water molecules, while charged groups are outside, in the contact with water. The polar groups promote low density Ih-type structure in the water outside this first hydration shell. When BLG unfolds it assumes a more extended configuration on which the previously buried nonpolar groups are exposed to water and promote the higher density II-type structure outside its first shell. Detailed assignments of bands attributed to the bulk water, different states of the hydrated water and the changed conformation of BLG are proposed.

• Bulletin of the Korean Chemical Society
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• 제2권2호
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• pp.66-71
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• 1981

The effects of cation on tRNA have been theoretically investigated using the semiempirical potential energy functions. The binding of $Mg^{2+}$ to the model compound and the hydration scheme of the anticodon loop have been determined, and their stabilization energies produced by the introduction of magnesium pentahydrate and water molecules in the first hydration shell were calculated. The results indicate that magnesium pentahydrate is important for decreasing the flexibility of the anticodon loop and satisfying the large Y37 stereochemically during the protein synthesis. The effects of $Mg^{2+}$ on the hydration scheme were also investigated.