• 한국축산식품학회지
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• 제32권5호
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• pp.627-634
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• 2012

This study was carried out to investigate the physical and thermal properties of ${\kappa}$-carrageenan (${\kappa}$-car) gel added whey protein isolate (WPI) as a cryoprotectant. The concentration of ${\kappa}$-carrageenan was fixed at 0.2 wt%. The mean ice crystal size of the WPI/${\kappa}$-car was decreased according to increasing whey protein isolate concentration. The temperature of gel-sol (Tg-s) and sol-gel (Ts-g) transition of WPI/${\kappa}$-car maxtrix was represented in the order of 3.0, 0.2, 5.0 and 1.0 wt%. In addition, the transition temperature of gel-sol of WPI in sucrose solution were showed in order of 1.0, 5.0, 0.2 and 3.0 wt% depending on whey protein isolate concentration. The shape of ice crystal was divided largely into two types, round and rectangular form. 1.0 wt% WPI/${\kappa}$-car matrix at pH 7 and 9 showed minute and rectangular formation of ice crystals and whey protein isolate in sucrose solution at a concentration of 1.0 wt% WPI/${\kappa}$-car matrix at pH 3 and 5 showed relatively large size and round ice crystals. The ice recrystallization characteristics and cryprotective effect of ${\kappa}$-carrageenan changed through the addition of different concentrations of whey protein isolate. It seems that the conformational changes induced interactions between whey protein isolate and ${\kappa}$-carrageenan affected ice recrystallization.

• BioChip Journal
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• 제12권4호
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• pp.317-325
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• 2018

This paper investigated the effects of ionic strength in the medium on a preconcentrator for a protein sample with low concentration. The preconcentration chip was designed and fabricated using a polydimethylsiloxane replica through standard lithophotography. A glass substrate is silanized prior to functionalizing the nanoparticles for self-assembly at a designed region. Due to the overlap of electrical double layers in a nanofluidic channel, a concentration polarization effect can be achieved using an electric field. A nonlinear electrokinetic flow is induced, resulting in the fast accumulation of proteins in front of the induced ionic depletion zone, so called exclusion-enrichment effect. Thus, the protein sample can be driven by electroosmotic flow and accumulated at a specific location. The chip is used to collect fluorescein isothiocyanate-labeled bovine serum albumin (FITC-BSA) diluted in phosphate-buffered saline (PBS) buffer solution. Different concentrations of the buffer media were studied herein. Fluorescence intensity images show that the buffer concentration of 4 mM is more appropriate than all the other ones. The sample of FITC-BSA with an initial concentration of $10{\mu}M$ in the 4 mM PBS solution increases its concentration at the desired region by up to 50 times within 30 min, demonstrating the results in this investigation.

• Journal of Photoscience
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• 제9권2호
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• pp.134-137
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• 2002

PYP consists of a water-soluble apoprotein and 4-hydroxycinnamyl chromophore bound to Cys69 via thiolester linkage, Upon absorption of a photon, the photocycle is initiated, leading to formation of several photo-intermediates. Among them, M intermediate is important to understand the signal transduction mechanism of PYP, because it is a putative signaling state. As well known, the dynamics of a protein is closely correlated with the occurrence of its function. Here we report the results of IO ns molecular dynamics (MD) simulation for the M intermediate in aqueous solution and discuss the characteristic feature of this state from a viewpoint of structural fluctuation.

• Bulletin of the Korean Chemical Society
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• 제25권7호
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• pp.1031-1035
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• 2004

The adsorption kinetics of ${\beta}$-casein on a hydrophobic surface has been studied by means of the quartz crystal microbalance (QCM). The self assembled monolayer of 1-octadecanethiol on a gold coated quartz crystal was used as a hydrophobic surface for adsorption. The adsorption kinetics was monitored in different solution conditions. Formation of monolayer is observed in most cases. At high concentration of protein, micelle formation which is interrupted by high ionic strength of solution is observed. Casein binding cations such as $Ca^{2+},\;Ba^{2+}\;and\;Al^{3+}$ increase the hydrophobicity of the protein and the multiple layer adsorption occurs. The strong and weak points of the QCM method in the study of protein adsorption are discussed.

• The Journal of the Acoustical Society of Korea
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• 제21권3E호
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• pp.126-131
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• 2002

Ultrasonic measurements are made in egg white to study the properties of the solution of the natural protein. The high-Q ultrasonic resonator method is used to get the ultrasonic absorption spectra over the range 0.2-10 ㎒ at 20℃. It is proportional to the 1.25th power of the frequency. The gelation process caused by heat is studied from the change in the velocity and the absorption. at 3 ㎒ using the pulse echo overlap technique over the range of 10-80℃. The absorption decreases with increasing temperature up to 60℃ where it turns up sharply and rapidly increases thereafter. The strong absorption in the gel region is described by the interaction between the solution and the network structure made of protein. Very slow variation in time elapse is observed after the temperature is quickly raised. It would be a real-time observation of the network building process and the characteristic time for the process is shown to be 400 min. A hysteresis phenomenon with respect to the temperature is observed. This phenomenon is associated with the memorizing effect of the network structure of protein of the gel.

• 한국자기공명학회논문지
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• 제8권1호
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• pp.19-27
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• 2004

C-terminal fragments of APP (APP-CTs), that contain complete Abeta sequence, are found in neuritic plaques, neurofibrillary tangles and the cytosol of lymphoblastoid cells obtained from AD patients. CT16, Lys649-Asp664 (KKQYTSIHHGVVEVD) has been known as the most toxic part in the C-terminal fragment of amyloid precursor protein (APP). The solution structure of CT16 was investigated using NMR spectroscopy in various membrane-mimicking environments. According to Circular Dichroim (CD) spectra, CT16 has a random structure in aqueous solution, while conformational change was induced by addition of TFE and SDS micelle. Tertiary structure as determined by NMR spectroscopy shows that CT16 has a ${\beta}$-turn conformation in trifluoroethanol-containing aqueous solution.

• 한국축산식품학회지
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• 제18권3호
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• pp.209-215
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• 1998

Effects of protein concentration, ionic strength, pH, and temperature range on the heat-induced denaturation of salt soluble protein extracted from spent layer meat were investigated. Viscosity of salt soluble protein heated at 65$^{\circ}C$ for 30 min began to increase sharply above 7 mg/ml of breast protein concentration, and above 21 mg/ml of leg protein concentration, respectively. Both turbidity and viscosity showed the highest value in cooked protein solution with pH 6.0 and 1% NaCl. The turbidity of salt soluble protein started to increase continuously from 40$^{\circ}C$ to 80$^{\circ}C$. The viscosity increased rapidly from 45$^{\circ}C$ to 60$^{\circ}C$ in breast protein, and increased from 50$^{\circ}C$ to 55$^{\circ}C$ in leg protein, respectively, and then kept relatively constant. Breast protein had higher viscosity than leg protein during heat-induced gelation. Therefore, salt soluble protein from spent layer meat was associated with denatured protein (turbidity change) prior to gelation (viscosity change) during heating. Breast protein showed lower thermal transition temperature, and better gel formation than leg protein during heating.

• Macromolecular Research
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• 제9권4호
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• pp.197-205
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• 2001

Platelet adhesion onto elastic polymeric biomaterials was tested in vitro by perfusing human whole blood at a shear rate of 100 sec$\^$-1/ for possible verification of mechanisms of initial platelet adhesion perfusion of blood on the polymeric substrates was performed after treatments either with or without pre-adsorption of 1% blood plasma, and either with or without residence of the protein-preadsorbed substrate in phosphate buffered solution. The surfaces employed were elastic polymers such as poly(ether urethane urea), poly(ether urethane), silicone urethane copolymer, silicone rubber and poly(ether urethane) with the anti-calcifying agent hydroxyethane bisphosphate. Each polymer surface treated was exposed in vitro to the dynamic, heparinized whole blood perfused for upto 6 min and the surface area of platelets initially adhered was measured by employing in situ epifluorescence video microscopy. The blood perfusion was performed on the surfaces treated at the following three different conditions: directly on the bare surfaces, after protein pre-adsorption and after residence in buffer for 3 days of the surfaces protein pre-adsorbed for 2 h. The effects of blood plasma pre-adsorption on the initial platelet adhesion was surface-dependent. The amount of the adsorbed fibrinogen and the surface coverage area of the adhered platelets were dependent on the surface conditions whether substrates were bare surfaces or protein pre-adsorbed ones. To test an effect of possible morphological (re)orientations of the adsorbed proteins on the initial platelet adhesion, the polymeric substrate pre-adsorbed with 1% blood plasma was immersed in phosphate buffered solution for 3 days and then exposed to physiological blood perfusion. The surface area of the platelets adhered on these surfaces was significantly different from that of the surfaces treated with protein pre-adsorption only. These results indicated that platelet adhesion was dependent on the surface property itself and pre-treatment conditions such as blood perfusion without any pre-adsorption of proteins, and blood perfusion either after protein pre-adsorption or after subsequent substrate residence in buffer of the substrate pre-adsorbed with proteins. Understanding of these results may guide for better designs of blood-contacting materials based on protein behaviors.

• Applied Biological Chemistry
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• 제36권2호
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• pp.121-126
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• 1993

참깨박에 함유되어 있는 불용성 형태의 단백질을 가용성 형태의 단백질로 용출시키기 위하여 Bacillus sp. CW-1121이 생성하는 효소를 작용시켰다. 이때 참깨박의 단백질 용출을 위한 최적 pH는 7.5였으며, 최적 온도는 $40^{\circ}C$였고 최적 조건하에서 2시간의 소화로 약 60%의 용해도를 보였다. 단백질의 용해도는 참깨 단백질이 pH4.5에서 가장 낮아 등전점을 보였고, pH3.0과 pH6.0 이상에서는 크게 증가하였다. 효소처리 참깨박 단백질을 전기영동한 결과 수용성 단백질은 4개, 염용성 단백질은 2개의 밴드가 관찰되었다. 분리 단백의 아미노산 조성은 수용성 단백질의 경우 serine이 17.24 mg/g, 염용성 단백질은 glutamic acid가 10.77 mg/g, 유리아미노산은 glutamic acid가 6.55 mg/g으로 가장 많이 함유되어 있었으며 특히 필수아미노산의 조성도 상당히 좋은 편이었다.

• 한국환경과학회지
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• 제7권1호
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• pp.41-45
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• 1998

The feasibility of foam separation to remove protein in aquacultural recirculating water was investigated. From the results of batch foam separation on protein removal, superficial air velocity and initial protein concentration in bulk solution were found to be important operational factors In determining removal rates of protein. The protein removal rate by batch foam separation was proportionally increased with the superficial air velocity. Performance characteristics of continous foam separator were highly dependent upon the operating parameters of superficial air velocity, hydraulic retention time(HRT) and foam height. Removal effeciency of protein increases with increasing superficial air velocity and HRT, and independent on foam height. As DO concentration was increased with superficial air velocity, foam separator is also used for oxygen addition. It could be confinned that foam separator might offer better perspective for protein removal in aquacuitural recirculating water.