• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.1
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• pp.17-24
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• 1997

The effects of steeping on the physicochemical and gelatinization characteristics of glutinous rice flour and its starch were studied. Steeping conditions were 1 day at 25"C,7 days at 2iC and 7 days at 35"C. Crude protein, lipid and ash content were decreased br steeping. It was observed with scanning electron microscopy that endosperm cell wall of glutinous rice flour was diminished by steeping. Although morphology of the glutinous rice starch granules was not affected, the size was decreased by steeping. Density and water binding capacity(WBC) of glutinous rice flour and its starch were changed by steeping. X-ray diffraction pattern of glutinous rice starch was A type and was not affected by steeping. Swelling power of glutinous rice flour and its starch was increased but solubility was decreased by steeping. In Brabender amylographic examination, peak viscosity of untreated glutinous rice flour was very low and increased enormously by steeping resulting in the similar Brabender viscosity pattern to its starch. The gelatinization temperature examined by X-ray diffractometry was lowered by steeping. And the degree of gelatinization under the conclusion temperature increased with increasing of steeping Period and temperature.mperature.

• BMB Reports
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• v.49 no.9
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• pp.497-501
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• 2016

Wide-line ¹H NMR intensity and differential scanning calorimetry measurements were carried out on the intrinsically disordered 73-residue full transactivation domain (TAD) of the p53 tumor suppressor protein and two peptides: one a wild type p53 TAD peptide with a helix pre-structuring property, and a mutant peptide with a disabled helix-forming propensity. Measurements were carried out in order to characterize their water and ion binding characteristics. By quantifying the number of hydrate water molecules, we provide a microscopic description for the interactions of water with a wild-type p53 TAD and two p53 TAD peptides. The results provide direct evidence that intrinsically disordered proteins (IDPs) and a less structured peptide not only have a higher hydration capacity than globular proteins, but are also able to bind a larger amount of charged solute ions.

• Journal of Pharmaceutical Investigation
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• v.40 no.4
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• pp.237-244
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• 2010

This study investigated basic material properties and compressibility of commonly used pharmaceutical excipients. Five classes of excipients are selected including starch, lactose, calcium phosphate, microcrystalline cellulose (MCC), and povidone. The compressibility was evaluated using compression parameters derived from Heckel and Kawakita equation. The Heckel plot for lactose and dicalcium phosphate showed almost linear relationship. However, for MCC and povidone, curves in the initial phase of compression were observed followed by linear regions. The initial curve was considered as particle rearrangement and fragmentation and then plastic deformation at the later stages of the compression cycle. The Kawakita equation showed MCC exhibited higher compressibility, followed by povidone, lactose, and calcium phosphate. MCC undergoes significant plastic deformation during compression bringing an extremely large surface area into close contact and facilitating hydrogen bond formation between the plastically deformed, adjacent cellulose particles. Lactose compacts are consolidated by both plastic deformation and fragmentation, but to a larger extent by fragmentation. Calcium phosphate has poor binding properties because of its brittle nature. When formulating tablets, selection of suitable pharmaceutical excipients is very important and they need to have good compression properties with decent powder flowability. Material properties tested in this study might give a good guide how to select excipients for tablet formulations and help the formulation scientists design the optimum ones.

• Journal of the Korean Vacuum Society
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• v.18 no.5
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• pp.384-389
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• 2009

ZnO, a wurtzite lattice structure, has attracted much attention as a promising material for light-emitting diodes (LEDs) due to highly efficient UV emission resulting from its large band gap of 3.37 eV, large exciton binding energy of 60 meV, and low power threshold for optical pumping at room temperature. For the realization of LEDs, both n-type ZnO and p-type ZnO are required. Now, n-type ZnO for practical applications is available; however, p-type ZnO still has many drawbacks. In this study, ZnO films were grown on glass substrates by using atomic layer deposition (ALD) and the ZnO films were irradiated by nitrogen ion beams (20 keV, $10^{13}{\sim}10^{15}ions/cm^2$). The effects of nitrogen-beam irradiation on the ZnO structure as well as the electrical property were investigated by using fieldemission scanning electron microscopy (FESEM) and Hall-effect measurement.

• Journal of the Korean Chemical Society
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• v.24 no.1
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• pp.25-33
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• 1980

Pyrocatechase as a phenolytic dioxygenase was extracted from the benzoate-induced cells of a soil bacterium, a member of Pseudomonadaceae, and purified partially by DEAE-cellulose ion-exchange chromatography and Sephadex G-75 gel filtration. Final preparation of the enzyme yielding 200 fold purification over the crude extracts showed a specific activity of about 40 ${\mu}moles$ per minute per mg protein based on catechol as the substrate. The enzyme showed a very limited substrate specificity towards catechol for its catalytic activity. Based on the inhibition study with the substrate analogues, it was assumed that ortho dihydroxy groups on the aromatic ring may participate in the enzyme-substrate binding. The $K_m$ value for catechol was obtained as $1.9{\times}10^{-6}M$, and the optimum activity of the enzyme was obtained at the pH range of 7∼10 and $35^{\circ}C$. With SH-group blocking agents the enzyme was inhibited seriously. The activity of enzyme was also inhibited by the addition of some heavy metals, $Ag^+$ and $Cu^{2+}$, but was not affected by EDTA. General property of the enzyme was characterized and the possible nature of the enzyme active center was also discussed.

• Korean Journal of Food Science and Technology
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• v.28 no.3
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• pp.514-520
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• 1996

The purpose of this study was to develop the production technology of modified starch. Corn starches were gamma irradiated at 0-110 kGy and the effect of irradiation dose levels on the physicochemical properties of corn starches were investigated. Blue value linearly decreased, while alkali number and solubility markedly increased as irradiation dose levels were increased. The optical transmittance increased as applied irradiation dose levels were increased in the temperature range of $65-95^{\circ}C.$ Water binding capacity and swelling power showed maximum value at 30 and 10 kGy, respectively and they tended to decrease thereafter. Gelatinization viscosity of the gamma irradiated starch considerably decreased as compared to that of the non-irradiated starch. Irradiation at 110kGy resulted in a marked reduction of peak viscosity and cooling viscosity at $30^{\circ}C$ by 100 and 300 times, respectively. The physicochemical properties of corn starch irradiated at 30 kGy were similar to those of commercial acid-modified starch, while those of corn starch irradiated at 100 kGy were similar to those if oxidized starch.

• Archives of Pharmacal Research
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• v.29 no.1
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• pp.50-58
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• 2006

Translationally controlled tumor protein (TCTP), also known as histamine releasing factor (HRF), is found abundantly in different eukaryotic cell types. The sequence homology of TCTP between different species is very high, belonging to the MSS4/DSS4 superfamily of proteins. TCTP is involved in both cell growth and human late allergy reaction, as well as having a calcium binding property; however, its primary biological functions remain to be clearly elucidated. In regard to many possible functions, the TCTP of Plasmodium falciparum (Pf) is known to bind with an antimalarial agent, artemisinin, which is activated by heme. It is assumed that the endoperoxide-bridge of artemisinin is opened up by heme to form a free radical, which then eventually alkylates, probably to the Cys14 of PfTCTP. Study of the docking of artemisinin with heme, and subsequently with PfTCTP, was carried out to verify the above hypothesis on the basis of structural interactions. The three dimensional (3D) structure of PfTCTP was built by homology modeling, using the NMR structure of the TCTP of Schizosaccharomyces pombe as a template. The quality of the model was examined based on its secondary structure and biological function, as well as with the use of structure evaluating programs. The interactions between artemisinin, heme and PfTCTP were then studied using the docking program, FlexiDock. The center of the peroxide bond of artemisinin and the Fe of heme were docked within a short distance of $2.6{\AA}$, implying the strong possibility of an interaction between the two molecules, as proposed. When the activated form of artemisinin was docked on the PfTCTP, the C4-radical of the drug faced towards the sulfur of Cys14 within a distance of $2.48{\AA}$, again suggesting the possibility of alkylation having occurred. These results confirm the proposed mechanism of the antimalarial effect of artemisinin, which will provide a reliable method for establishing the mechanism of its biological activity using a molecular modeling study.

• Korean Chemical Engineering Research
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• v.49 no.4
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• pp.387-392
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• 2011

Enzymes are being used in various fields due to their unique property of substrate specificity. Enzyme-linked immunosorbent assay(ELISA) has enabled the detection of various antigens by reporting the binding event of antigen and antibody via enzyme-catalyzed reaction. However, the sensitivity improvement of conventional ELISA has been limited because only one enzyme molecule is conjugated to one molecule of antibody. To overcome this limitation and further improve the sensitivity of ELISA, there have been efforts to increase the number ratio of enzymes to antibody. Recently, the nanobiocatalytic approaches, with their successful enzyme stabilization, improved the performance stability as well as sensitivity in a modified protocol of ELISA. The present paper introduces the basic principle of ELISA, and the recent efforts to improve sensitivity and performance stability of ELISA by using the nanobiocatalytic approaches.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.4B
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• pp.191-199
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• 2007

Mobile node has to register its current location to Home Agent when it moves to another network while away from home. However, the registration procedure cannot be completed successfully when Home Agent is protected by the VPN gateway which guards MN's home network and discards the unauthorized packets incoming from outside as a lack of security association(SA) between the Care-of address and security policy of the home network so that the binding registration message without SA is discarded smoothly by the VPN gateway. This paper presents the authentication and key exchange scheme using the AAA infrastructure for a user in Internet to access the home network behind the VPN gateway. By defining the role of authentication and tunnel processing for each agent or relay entity, this paper presents the procedure to register the current location to its Home Agent with secure manner. Performance result shows cost improvement up to 40% comparing with existing scheme in terms of the packet loss cost, the property of mobility and traffic.

• Food Science and Preservation
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• v.14 no.4
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• pp.394-399
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• 2007

In this study, the characteristic qualities of whole soymilk were examined based on differing hydrolysis condition. The results showed that as the concentration of enzyme preparation(KMF-G) increase, $^{\circ}Brix$, calcium-binding capacity, and the content of free amino acid components also increased. Additionally SDS-PAGE analysis revealed a similar pattern of in the molecular weight of proteins at enzyme preparation concentration 0.20 and 0.35%(w/w). The quality of whole soymilk hydrolysate was shown to be best at a enzyme preparation(KMF-G) concentration of 0.20%(w/w) and hydrolysis time of 60 min. When sterilized at 115, 130 and $145\;^{\circ}C$ for 15 sec each the change in whole soymilk quality was not substantial. Based on the above results, a 0.20%(w/w) enzyme preparation(KMF-G) concentration and 60 mim hydrolysis time was determined to be the optimal hydrolysis condition for whole soymilk. It is anticipated that soymilk hydrolysis will a food material that is diverse in its application and uses.