• Archives of Pharmacal Research
• /
• v.25 no.3
• /
• pp.381-386
• /
• 2002

The objective of this study was to link conformational changes of proteins at a water/methylene chloride interface to their destabilization upon emulsification. When 4 aqueous protein solutions (bovine serum albumin, $\beta$-lactoglobulin, ovalbumin, or ribonuclease) were emulsified in methylene chloride, considerable proportions of all the proteins became water insoluble aggregates. There were also noticeable changes in the compositions of their water-soluble species. A series of water/methylene chloride interfacial reactions upon the proteins was considered a major cause of the phenomena observed. Based on this supposition, the interfacial tension was determined by a Kruss DVT-10 drop volume tensiometer under various experimental conditions. It substantiated that the interfacial tension was high enough to cause the adsorption of all the proteins. Under our experimental conditions, their presence in the aqueous phase resulted in reductions of the interfacial tension by the degrees of 8.5 - 17.1 mN $m^{-1}$. In addition, dynamic changes in the interfacial tension were monitored to compare relative rates at which the adsorbed proteins underwent conformational, structural rearrangements at the interface. Such information helped make a prediction about how easily proteins would denature and aggregate during emulsification. Our study indicated that emulsifying aqueous protein solutions in organic solvents should be handled with care, due to adverse interfacial effects.

• Journal of Integrative Natural Science
• /
• v.9 no.4
• /
• pp.249-254
• /
• 2016

This study evaluated the physical and optical characteristics of hydrophilic ophthalmic polymer with addition of 2-methacryloyloxyethyl phosphorylcholine in the basic hydrogel ophthalmic lens material, and in particular, the utility of 2-methacryloyloxyethyl phosphorylcholine as an ophthalmic contact lens material for ophthalmologic devices was investigated. In this study 2-methacryloyloxyethyl phosphorylcholine were used as additives. For the preparation of hydrogel lens 2-hydroxyethyl methacrylate, methyl methacrylate, acrylic acid and a cross-linker EGDMA were copolymerized in the presence of AIBN as an initiator. The physical properties of the produced polymers were measured as followings. The refractive index of 1.433~1.393, water content of 35.95~53.16%, contact angle of $70.6{\sim}51.24^{\circ}$, UVB transmittance of 81.2~82.4%, UV-B transmittance of 81.2~82.4% and visible transmittance of 91.4~92.2% were obtained. Also, in case of protein absorption, the measurement showed that absorbance of Reference and MPC-10 sample was 0.2598 and 0.2250 respectively. Based on the results of this study, ophthalmic lens material containing 2-methacryloyloxyethyl phosphorylcholine is expected to be used usefully as a material for high wettability and inhibitor of protein adsorption for ophthalmic hydrogel lens.

• Proceedings of the Korean Society of Dyers and Finishers Conference
• /
• 2011.03a
• /
• pp.43-43
• /
• 2011

• Proceedings of the KOSOMBE Conference
• /
• v.1992 no.11
• /
• pp.123-126
• /
• 1992

• Korean Journal of Food Science and Technology
• /
• v.46 no.3
• /
• pp.315-322
• /
• 2014

Immobilized lipases were prepared by physical adsorption using lipase AK, AY, AH, PS and R on Amberlite$^{(R)}$XAD$^{(R)}$7 HP resin. With the immobilized lipases (10%), structured lipid was synthesized by enzymatic interesterification of canola oil, palmitic ethyl ester, and stearic ethyl ester in order to study the reaction characteristics. Among the lipase, the highest protein content was obtained from lipase AH (11.41%) before immobilization, while the highest levels of bound protein was observed from immobilized lipase AK (63.91%). Immobilized lipase AK had the highest interesterification activity (38.3% of total saturated fatty acid). Lipase AK was also used for a continuous reaction in which the slow flow of reactant resulted in increased reaction rate. Reusability of immobilized AK, AH and PS increased at the second reaction (120-196.5%). However, the activity of immobilized AK, which had the highest bound protein content (63.91%) decreased after the third reaction, while the activity of immobilized AH and PS was maintained until the sixth reaction.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.411.2-411.2
• /
• 2014

The design of DNA nanostructures is of fundamental importance, the intrinsic value of DNA as a building-block material lies in its ability to organize other bio-molecules with nanometer-scale spacing. Here, we report the fabrication of DNA scaffolds with nano-pores (<10 nm size) that formed easily without the use of additives (i.e., avidin, biotin, polyamine, or inorganic materials) into large-scale structures by assembling DNA molecules at near room temperature ($30^{\circ}C$) and low pH (~5.5). Protein immobilization results also confirmed that a fibronectin (FN) proteins/large scale DNA scaffolds/aminopropylytriethoxysilane (APS)/SiO2/Si substrate with high sensitivity formed in a well-defined manner. The DNA scaffolds can be applied for use with DNA-based biochips, biophysics, and cell biology.

• Proceedings of the Membrane Society of Korea Conference
• /
• 1994.10a
• /
• pp.72-73
• /
• 1994

Whey는 일명 lactoserum 이라고도 하며 치즈제조시 우유를 응고시키는 과정에서 Casein과 지방으로부터 분리되어 나오는 액상의 부산물로 본래 우유 부피의 약 90%를 차지하며, 용해성 단백질, 유당, 비타민과 무기질 등을 함유하고 있다. 유청에 함유되어 있는 단백질은 건조고형분의 약 13%가 되는데, 주요 단백질은 $\beta$-lactoglobulin(50%), $\alpha$-lactalbumin(22%), Serum albumin(5%), Immunoglobulin(12%), Proteose-peptone(10%) 등이 있다. 유청단백질중 가장 많이 함유되어 있는 $\beta$-lactoglobulin은 구형의 단백질로 단량체의 분자량은 약 18,400이며, pH 3.5~7 범위내에서는 해리되지 않는 이량체(dimer)를 형성한다. pH 3.5 이하에서 이량체는 해리되고 다량체의 형성으로 재평성한다. pH 7.0 이상의 알칼리 영역에서는 Conformational Change가 일어나는 것으로 알려져 있으며, 등전점(isoelectric point)은 pH 5.2이다. $\alpha$-lactalbumin은 14,200의 분자량을 가지는 구형의 단백질로 등전점은 pH 4.8이다.

• Preventive Nutrition and Food Science
• /
• v.13 no.3
• /
• pp.204-211
• /
• 2008

Fish protein hydrolysates (FPHs) with different degrees of hydrolysis by treatment with alcalase, pronase, flavourzyme and trypsin and isolated peptide were prepared from Hwangtae (yellow dried pollack, Theragra chalcogramma). Hwangtae protein hydrolysate was fractionated according to the molecular weight into six major types of APO1 (1.3 kDa), APO2 (1 kDa), APO3 (<1 kDa), APACE (<1 kDa), APG1 (70 kDa) and APG2 (70 kDa) isolated from the hydrolysate using consecutive chromatographic methods. Soluble peptide were produced from Hwangtae and evaluated for their nutritional and functional properties. Some functional properties of FPHs were assessed and compared with those of egg albumin or the soybean protein. APO2 had the highest nitrogen solubility value (94.2%), emulsion capacity and emulsion stability of the Alaska Pollack peptide ranged from 12.4 to 39.5 (mL of oil per 200 mg of protein) and 44.0% to 77.5%, respectively. Highest and lowest fat adsorption values were observed for APG1 (9.9 mL of oil per gram of protein) and APO3 (3.8 mL of oil per gram of protein), respectively.

• Smart Structures and Systems
• /
• v.8 no.1
• /
• pp.17-37
• /
• 2011

The microcantilever (MCL) sensor is one of the most promising platforms for next-generation label-free biosensing applications. It outperforms conventional label-free detection methods in terms of portability and parallelization. In this paper, an overview of recent advances in our understanding of the coupling between biomolecular interactions and MCL responses is given. A dual compact optical MCL sensing platform was built to enable biosensing experiments both in gas-phase environments and in solutions. The thermal bimorph effect was found to be an effective nanomanipulator for the MCL platform calibration. The study of the alkanethiol self-assembly monolayer (SAM) chain length effect revealed that 1-octanethiol ($C_8H_{17}SH$) induced a larger deflection than that from 1-dodecanethiol ($C_{12}H_{25}SH$) in solutions. Using the clinically relevant biomarker C-reactive protein (CRP), we revealed that the analytical sensitivity of the MCL reached a diagnostic level of $1{\sim}500{\mu}g/ml$ within a 7% coefficient of variation. Using grazing incident x-ray diffractometer (GIXRD) analysis, we found that the gold surface was dominated by the (111) crystalline plane. Moreover, using X-ray photoelectron spectroscopy (XPS) analysis, we confirmed that the Au-S covalent bonds occurred in SAM adsorption whereas CRP molecular bindings occurred in protein analysis. First principles density functional theory (DFT) simulations were also used to examine biomolecular adsorption mechanisms. Multiscale modeling was then developed to connect the interactions at the molecular level with the MCL mechanical response. The alkanethiol SAM chain length effect in air was successfully predicted using the multiscale scheme.

• 한국생물공학회:학술대회논문집
• /
• 2000.04a
• /
• pp.149-152
• /
• 2000

In recent years, various artificial molecular photodiode have been fabricated by mimicking the electron transport function of biological photosynthesis. And now, we have been investigated the protein-organic hetero thin film photodiode using GFP as an sensitizer based on the redox potential difference of functional molecules. In this paper, shows molecular photodiode consisting of green fluorescence protein(GFP). viologen and TCNQ. The TCNQ and viologen were deposited onto ITO coated glass by LB technique. And GFP molecule was adsorption onto the viologen LB film surface by self-assembly method. Finally, The Al deposition onto GFP/viologen/TCNQ film surface was performed to make a top electrode. As a result, The MIM(metal/Insulator/Metal) structured device was constructed. The input light of 460nm wavelength was generated by the xenon lamp system, and then the photocurrent produced from the molecular device was detected through a current-voltage(I-V) measuring unit (SMU Model 236, Keithley, USA). An artificial molecular photodiode using protein(GFP)-adsorbed hetero-LB film is presented as a model system for the bioelectronic device based on the biomimesis.