• Korean Journal of Food Science and Technology
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• v.19 no.2
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• pp.89-96
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• 1987

The denaturation mechanism of the protein during heating of myosin and paramyosin extracted from the ordinary muscle of yellowtail (Seriola qrinqueradits) and the adductor muscle of whelk (Neptunea arthritica cuming) were investigated by analyzing the hydrophobicity, solubility, SH group and protein-protein interaction. The free hydrophobic residue of the two proteins were increased by increase of heating temperature up to $65^{\circ}C$ and then decreased for further temperature raise. The protein-protein interaction was proportional to the increment of the free hydrophobic residue. The aggregation of protein was begun from $65^{\circ}C$ with the decrease of the free hydrophobic residues. The results of Arrhenius equation for the data on proteinprotein interaction showed that the denaturation course was made up with multi-steps in the myosin and two-steps in the paramyosin. The number of free hydrophobic residue and SH group, solubility and protein-protein interaction were significantly differed with the denaturation temperature (p<0.01).

• Analytical Science and Technology
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• v.11 no.6
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• pp.413-420
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• 1998

The hydrophobic interaction has been studied on sodium naphthalene derivatives such as sodium 1-naphthaleneacetate (S1NA), sodium 1-naphthalenemalonate (SINM), sodium 2-naphthaleneacetate (S2NA), and sodium 2-naphthalenepropionate (S2NP) in $H_2O$-MeOH mixture solutions and in surfactant solutions. In $H_2O$-MeOH mixture solutions, the hydrophobic interaction was measured, and resulted in the red shift in emission spectra. In cationic surfactant, cetyltrimethylamonium bromide (CTAB) solution, the hydrophobic interaction was also observed by the red shift in absorption and emission spectra.

• Journal of the Korean Chemical Society
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• v.29 no.1
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• pp.31-37
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• 1985

N-Acetyl-1-phenylalanyl-1-phenylalanine methyl ester (APhPhMe), N-acetyl-l-phenylalanine methyl ester (APhMe) and N-acetyl-1-phenylalanyl-1-alanine methyl ester (APhAlMe) were used as model compounds to investigate a protein denaturation under various temperatures and pressures. Overall, the solubility of APhPhMe in water increased with increasing pressure and that of APhMe decreased. However, the solubility of APhAlMe was nearly same. The values of volume change of APhPhMe were -0.9, -1.47, -1.09, -1.52 ml/mole at 20, 30, 40 and 50$^{\circ}C$, respectively, and those of APhMe were +6.0, +7.0, +7.5 ml/mole at 20, 30 and 40$^{\circ}C$, respectively. But those of APhAlMe were nearly zero at the measured temperature. The experimental result seems to be explained by the hydrophobic interaction and hydrogen bond of peptide bonds. In the compounds which have only peptide bonds and which have both a pretty large hydrophobic group and a peptide bond in the molecules, the hydrogen bond between peptide bonds is more dominant than the hydrophobic interaction. However, when the number of peptide bond and hydrophobic group increase simultaneously, the hydrophobic interaction seems to be more dominant.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1995.06a
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• pp.253-254
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• 1995

• Proceedings of the Korean Information Science Society Conference
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• 2004.04b
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• pp.310-312
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• 2004

이 논문에서는, 단백질의 상호작용을 다양한 아미노산의 속성과 Support Vector Machine(SVM)을 사용하여 예측하였다. SVM을 사용한 단백질 상호작용의 예측 시스템에 단백질 상호작용에 중요한 작용을 하는 아미노산의 속성을 사용하고 있다. 이번 실험은 9가지의 아미노산의 속성의 조합 즉, 511(2$^{9}$ -1)가지의 아미노산 속성을 SVM 학습데이터로 사용하여 예측시스템의 결과를 비교한다. 실험에는 Database of Interacting Proteins(DIP)를 사용하였다. 실험을 위하여 DIP의 H.pylori를 학습용데이터로 사용하고, E.coli를 예측데이터(검증데이터)로 사용하였다. 실험에 따르면 H.pylori의 학습데이터와 E.coli를 예측데이터의 가공에 '소수성'을 사용한 방법보다 '방향성'을 사용한 방법이 더 높은 수치를 나타냈다.

• Journal of the Korean Applied Science and Technology
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• v.29 no.2
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• pp.278-285
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• 2012

Effects of ion species on the expansion behavior of Poly(styrene sufonic acid)(PSSA) hydrogel were investigated in aqueous solution of selected anions, cations and hydrophobic ions. The deexpansion extent of Poly(stylene sulfonic acid) gel follow the sequence $SCN^-$<$Br^-$<$Cl^-$<$F^-$ in low concentration solutions due to the destabilization of anions to hydrogen bond between ${SO_3}^-$ and water. The deexpansion in cations followed the sequence of counterion interactions between ${SO_3}^-$ and cations. It was discussed the effects of ions on the hydrogen bonding through ${SO_3}^-$ and phenyl ring in salt solutions. Other interactions, such as the cation-${\pi}$ interaction, hydrophobic interaction, and dispersion force, contributed to the ion specific swelling of PSSA hydrogel.

• Proceeding of EDISON Challenge
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• 2017.03a
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• pp.158-164
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• 2017

암을 억제시키는 기능을 하는 단백질로 잘 알려진 p53은, 주로 종양세포에서 과도하게 발현되는 단백질인 HDM2와 복합체를 형성하여 비활성화되고 항암기능을 상실하게 됩니다. 때문에 종양세포에서의 p53-HDM2의 상호작용을 억제하기 위해 현재까지 많은 연구가 진행되어왔으며, 다양한 p53-HDM2 억제제가 개발된 바 있습니다. 최근 연구들에 따르면, HDM2와 결합친화도를 높이고 소수성 작용(hydrophobic interaction)에 기여하여 보다 안정한 구조를 만드는 탄화수소체인(staple)을 연결시킨 펩타이드 설계에 대한 관심이 높아지고 있는 추세입니다. 이에, 본 연구에서는 분자동역학 모의실험을 통해서 얻은 탄화수소체인-p53과 비탄화수소체인-p53 및 각각의 HDM2와 결합한 복합체를 기반으로 EDISON의 용매화 자유에너지(Solvation Free Energy) 프로그램을 이용하여 탄화수소체인의 특징 및 역할을 구조적인 측면과 열역학적인 측면으로 분석하여 비교하고자 합니다. 우리 연구에서 비탄화수소체인-p53의 구조는 분자동역학 시뮬레이션을 수행하는 동안 나선구조형태로 풀려 HDM2와 결합 유도 시에 주요결합 아미노산 잔기가 올바른 결합부위와 상호작용하지 못한 결과를 확인한 반면, 탄화수소체인이 형성된 구조는 시뮬레이션 동안에도 펩타이드의 나선구조를 유지시켜 HDM2와 주요 결합을 형성하는 아미노산 잔기들을 올바른 방향으로 배치시켜 HDM2와의 결합친화도를 높였습니다. 이 연구 결과는 탄화수소체인이 펩타이드의 나선성을 유지시키고, HDM2와의 상호작용을 통한 구조적인 안정성 유도 및 용매화 자유에너지에 큰 기여를 통해 p53-HDM2상호작용 억제제에서 긍정적인 역할을 할 가능성을 보여줍니다.

• Journal of the Korean Chemical Society
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• v.63 no.6
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• pp.427-434
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• 2019

The role of hydrophobic residues on protein folding reaction was studied by folding kinetics measurements in conjunction with protein engineering. The HubWA, which was derived from human ubiquitin by mutating the residues at 45 (Phe to Trp) and 26 (Val to Ala), was used as a mutational background. Fourteen hydrophobic residues were mutated to alanine. Among fourteen variants generated, only four variant proteins (V5A, I13A, V17A, and I36A) were suitable for folding study. The folding kinetics of these variants was measured by stopped-flow fluorescence spectroscopy. The folding kinetics of HubWA and V17A was observed to follow a three-state on-pathway mechanism. On the other hand, folding kinetics of V5A, I13A, and I36A was observed to follow a two-state mechanism. Based on these observations, transition of protein folding reaction from collision-diffusion mechanism to nucleation-condensation mechanism was discussed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.15-18
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• 2006

Recently, experimental visualization of microscale fluid transport has attacted considerable attention in designing microelectromechanical systems. Fluid-surface interactions on hydrophobic and hydrophilic surfaces can play a key role in passively controlling microfluidics. Here we investigate the slip boundary condition depending on the surface characteristics; hydrophilic, hydrophobic wettabilities. Using the micro-PIV, velocity profiles are measured in the glass (hydrophilic), PDMS (hydrophobic) microchannels.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05c
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• pp.507-512
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• 1996

저준위 방사성 폐액의 전처리공정으로써 한외여과막의 적용성을 평가하기 위해서 폐액내에 있는 오일과 계면활성제의 상호작용을 규명하고 오일에멀젼 용액의 fouling정도를 조사하였다. 막의 fouling을 감소시키는 한 방법으로 계면활성제에 의해 막의 표면을 개질하므로서 막투과 flux는 크게 증가되는 효과를 얻었다. 친수성막과 소수성막에 대하여 몇가지 계면활성제로 처리한 후 성능을 비교한 결과 소수성인 폴리솔푼막에 대한 SDS의 표면개질이 가장 유리하였다. 표면처리 막의 적용성을 평가한 결과 미량의 계면활성제나 염이 포함된 오일에멀젼 용액에 대해서는 매우 우수한 투과 성능을 얻을 수 있으나 CMC 이상의 계면활성제가 포함된 오일용액에 대해서는 처리가 불가능하였다.