• Bulletin of the Korean Chemical Society
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• 제15권9호
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• pp.748-751
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• 1994

Poly(ethylene oxide) (PEO) in aqueous solutions has a hydrophobic character which can induce the hydrophobic interaction between its nonpolar parts. The hydrophobic properties of aqueous PEO solutions are studied by the viscometry in terms of the water structure-making and -breaking capabilities of added solutes of ureas. The results show that the contracted conformation of PEO of low molecular weight, namely poly(ethylene glycol) (PEG), does not result from the hydrophobic interaction between the nonpolar parts of PEO but it can participate in a hydrophobic interaction between the nonpolar parts of PEO and added ureas solutes with nonpolar groups, which can induce a large hydrodynamic volume and increase the viscosity. On the other hand, the PEO of large molecular weight seems to behave like any other water soluble polymers with nonpolar parts and its conformation in aqueous solutions is well explained in terms of water structure perturbing capabilities of added ureas.

• 분석과학
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• 제11권6호
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• pp.413-420
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• 1998

물-메탄올 혼합 용액과 계면활성제 용액에서 1-나프탈렌아세트산 나트륨염, 1-나프탈렌말론산 나트륨염, 2-나프탈렌아세트산 나트륨염과 2-나프탈렌프로피온산 나트륨염과 같은 나프탈렌 나트륨 유도체들의 소수성 상호작용에 대해서 연구하였다. 물-메탄올 혼합 용액에서 소수성 상호작용을 측정하였고, 방출선은 red shift가 일어났다. 양이온 계면활성제인 세틸트리메틸암모늄 브롬화 용액에서도 흡수, 방출선은 red shift됨을 보여주었다.

• Journal of Photoscience
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• 제11권2호
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• pp.65-69
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• 2004

The mechanism of interaction of four coumarin derivatives (CDS) with bovine serum albumin (BSA) was studied using spectrofluorometric technique. It was found that the coumarin ring common to all CDS makes major contribution to interaction. Binding affinities could be related to parachor values of CDS. Stem-Volmer plots indicated the presence of static component in the quenching mechanism. Results also showed that both tryptophan residues of protein are accessible to CDS. The high magnitude of rate constant of quenching indicated that the process of energy transfer occurs by intermolecular interaction forces and thus CDS binding site is in close proximity to tryptophan residues of BSA. Binding studies in the presence of the hydrophobic probe, 8-anilino-l-naphthalein-sulfonic acid showed that there is hydrophobic interaction between CDS and the probe and they do not share common sites in BSA. Thermodynamic parameters obtained from data at different temperatures showed that the binding of CDS to BSA involve hydrophobic bonds predominantly. The effects of various metal ions on the binding of CDS with BSA were also investigated.

• 대한화학회지
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• 제29권5호
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• pp.533-538
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• 1985

Spermine에 의하여 誘發되는 凝縮 DNA 構造의 安定化에 있어서 hydrophobic interaction의 重要性을 試驗하기 위하여 spermine-DNA 複合體의 異例的 吸光度-溫度 樣相에 미치는 urea의 效果를 調査하였다. 그 結果 異例的 吸光度-溫度 樣相의 downward peak(trough) 領域에 이르는 相變移에 對한 cooperativity, enthalpy, midpoint의 값들이 Tm 領域의 값들 보다 urea에 敏感한 影響을 받았으며, urea의 濃度 增加에 따라 downward peak가 점차 사라졌다. 이 data는 異例的 吸光度-溫度 樣相을 構成하는 downward peak가 spermine에 의하여 誘發되는 hydrophobic interaction에 의한 凝縮된 tertiary structure의 形成을 나타내고 있다고 불 수 있다.

• Journal of Photoscience
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• 제12권1호
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• pp.25-32
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• 2005

Binding of N-Alkyl phenothiazines (NAP) to bovine serum albumin (BSA) was studied by spectroscopic methods.It was found that the phenothiazine ring common to all drugs makes major contribution to interaction. However, the nature of alkylamino group at position 10 influences the protein binding significantly. Stern-Volmer plots indicated the presence of static component in the quenching mechanism. The high magnitude of rate constant of quenching indicated that the process of energy transfer occurs by intermolecular interaction and thus the drug-binding site is in close proximity to tryptophan residues of BSA. Binding studies in presence of hydrophobic probe, 8-anilino-1-naphthalein-sulphonic acid showed that there is hydrophobic interaction between drug and the probe and they do not share common sites in BSA. Thermodynamic parameters obtained from data at different temperatures showed that the binding of NAP to BSA predominantly involve hydrophobic forces. The effects of some cations and anions common ions were investigated on NAP-BSA interactions. The CD spectrum of BSA in presence of drug showedthat binding of drug leads to change in the helicity of the protein.

• Bulletin of the Korean Chemical Society
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• 제21권4호
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• pp.412-418
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• 2000

Association of cytochrome c with anionic membranes involved both electrostatic and hydrophobic interactions and their relative contributions depended on the physical state of the membrane and the redox state of cyto-chromec.Hydrophobic interaction was favored by the membranes in gel phase, by the membranes with a large curvature, and by the membranes with a high surface charge density. Ferrocytochrome c was less dissociable by NaCl than ferricytochrome c suggesting that a lower protein stability is beneficial for hydrophobic interac-tion.Hydrophobic interaction induced larger structural perturbations on cytochrome c as monitored by the loss of the Fe-Met bond and by the increase in the distance between heme and Trp-59. When bound to anionic mem-branes,spin-labeled cytochrome c showed an electron paramagnetic resonance spectrum with two or more components, providing a direct evidence for multiple conformations of bound cytochrome c.

• Bulletin of the Korean Chemical Society
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• 제10권2호
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• pp.158-161
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• 1989

The hydrophobic interaction occurring between rhodamine 6G and tetraphenylborate anions has been investigated with surfactants by absorption and fluorescence studies. In the order of tetraphenylborate, tetrakis(4-fluorophenyl)borate, and tetrakis[3,5-bis(trifluoromethyl)phenyl]borate the hydrophobicity is found to be increased.

• 한국염색가공학회지
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• 제14권2호
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• pp.85-85
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• 2002

The interaction between berberine and tannin in aqueous solution was investigated spectrophotometerically. The dyeing mechanism of silk fabrics (control and tannin treated silk fabrics) with berberine was based on thermodynamic parameters obtained from equilibrium adsorption experiments. In adsorption spectra of aqueous solution of berberine and tannin mixture two isosbestic points (328nm, 357nm) were found and the mole fraction of reaction of components was 1:1. Initial dyeing rates were increased and the diffusion of dye was more effective by tannin treatment. Without regard to tannin treatment the adsorption isotherm of berberine was the langmuir type except high temperature, 80℃. By tannin treatment the saturation dye uptake was increased, the increase of dye uptake appeared to be a result of entropy change rather than enthalpy change. All these results can be interpreted by the hydrophobic interaction between berberine and silk treated with tannin and it is reasonable to conclude that not only the ionic force, but also the hydrophobic interaction contributes to the binding of berberine and tannin treated silk treated with tannin.

• 한국염색가공학회지
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• 제14권2호
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• pp.9-17
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• 2002

The interaction between berberine and tannin in aqueous solution was investigated spectrophotometerically. The dyeing mechanism of silk fabrics (control and tannin treated silk fabrics) with berberine was based on thermodynamic parameters obtained from equilibrium adsorption experiments. In adsorption spectra of aqueous solution of berberine and tannin mixture two isosbestic points (328nm, 357nm) were found and the mole fraction of reaction of components was 1:1. Initial dyeing rates were increased and the diffusion of dye was more effective by tannin treatment. Without regard to tannin treatment the adsorption isotherm of berberine was the langmuir type except high temperature, $80^\circ{C}$. By tannin treatment the saturation dye uptake was increased, the increase of dye uptake appeared to be a result of entropy change rather than enthalpy change. All these results can be interpreted by the hydrophobic interaction between berberine and silk treated with tannin and it is reasonable to conclude that not only the ionic force, but also the hydrophobic interaction contributes to the binding of berberine and tannin treated silk treated with tannin.

• BMB Reports
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• 제39권5호
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• pp.636-641
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• 2006

Our previous studies indicated that native carbonic anhydrase does not interact with hydrophobic adsorbents and that it acquires this ability upon denaturation. In the present study, an apo form of the enzyme was prepared by removal of zinc and a comparative study was performed on some characteristic features of the apo and native forms by far- and near-UV circular dichroism (CD), intrinsic fluorescent spectroscopy, 1-anilino naphthalene-8-sulfonate (ANS) binding, fluorescence quenching by acrylamide, and Tm measurement. Results indicate that protein flexibility is enhanced and the hydrophobic sites become more exposed upon conversion to the apo form. Accordingly, the apo structure showed a greater affinity for interaction with hydrophobic adsorbents as compared with the native structure. As observed for the native enzyme, heat denaturation of the apo form promoted interaction with alkyl residues present on the adsorbents and, by cooling followed by addition of zinc, catalytically-active immobilized preparations were obtained.