• BMB Reports
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• v.33 no.2
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• pp.172-178
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• 2000

The lipoxygenase was purified 35 fold to homogeneity from the Korean red potato by an ammonium sulfate precipitation and DEAE-cellulose column chromatography. The simple purification method is useful for the preparation of pure lipoxygenase. The molecular weight of the enzyme was estimated to be 38,000 by SDS-polyacrylamide gel electrophoreses and Sepharose 6B column chromatography. The purified enzyme with 2 M $(NH_4)_2SO_4$ in a potassium phosphate buffer, pH 7.0, was very stable for 5 months at $-20^{\circ}C$. Because the purified lipoxygenase is very stable, it could be useful for the screening of a lipoxygenase inhibitor. The optimal pH and temperature for lipoxygenase purified from the red potato were found to be pH 9.0. and $30^{\circ}C$, respectively. The Km and Vmax values for linoleic acid of the lipoxygenase purified from the red potato were $48\;{\mu}M$ and $0.03\;{\mu}M$ per minute per milligram of protein, respectively. The enzyme was insensitive to the metal chelating agents tested (2 mM KCN, 1 and 10mM EDTA, and 1 mM $NaN_3$), but was inhibited by several divalent cations, such as $Cu^{++}$, $Co^{++}$ and $Ni^{++}$. The essential amino acids that were involved in the catalytic mechanism of the 5-lipoxygenase from the Korean red potato were determined by chemical modification studies. The catalytic activity of lipoxygenase from the red potato was seriously reduced after treatment with a diethylpyrocarbonate (DEPC) modifying histidine residue and Woodward's reagent (WRK) modifying aspartic/glutamic acid. The inactivation reaction of DEPC (WRK) processed in the form of pseudo-first-order kinetics. The double-logarithmic plot of the observed pseudo-first-order rate constant against the modifier concentration yielded a reaction order 2, indicating that two histidine residues (carboxylic acids) were essential for the lipoxygenase activity from the red potato. The linoleic acid protected the enzyme against inactivation by DEPC(WRK), revealing that histidine and carboxylic amino acids residues were present at the substrate binding site of the enzyme molecules.

• The Korean Journal of Food And Nutrition
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• v.13 no.4
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• pp.342-347
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• 2000

The stabilization of barley $\beta$-amylase(Biozyme ML, Amano) was attained by modification with periodate-oxidized soluble starch. The specific activities of modified enzyme at pH 9.7 and pH 8.0 were 42% and 92%, respectively, compared with that of native enzyme. The pH stability of modified enzyme was increased at pH 2~5 and 7~12 in the presence of $\alpha$-cyclodextrin( $\alpha$ -CD) compared wish that of native enzyme. Thermal stability of the modified enzyme was increased. After treatment at 6$0^{\circ}C$ for 10min. the activity remained 8% for the enzyme modified at pH 8.0 in the presence of $\alpha$-CD, 4.5% for the native enzyme. The native enzyme and modified enzyme showed two peak in HPLC. The molecular weight of the modified enzyme was slightly increased in HPLC analysis.

• Elastomers and Composites
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• v.42 no.2
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• pp.75-85
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• 2007

In this study, the new adhesion system was studied to improve the adhesion strength between polyester cord and rubber matrix. In order to enhance the adhesion strength through polyester cord's surface treatment, the NaOH solution was used. The NaOH solution concentrations of 0.03, 0.05, 0.1, 0.2, 0.5, 1 and 5 wt.% were used in surface modifying the polyester cord. The optimum condition showing the maximum adhesion strength of polyester cord with SBR compound containing bonding agent was at NaOH concentration of 0.05 wt.% with treatment time of 10 minutes. When the NaOH solution concentration was above 1 wt.%, the polyester cord due to the excess surface modification was damaged, and resulted in breakage during the adhesion test. Also, the adhesion strength between polyester and SBR could be improved by coating the polyester cord with triallylcyanurate(TC) adhesive. The drying condition of polyester cord coated with TC attributed to the adhesion strength. The maximum adhesion strength was obtained by using the polyester cord dried at $220^{\circ}C$ rather than dried at room temperature.

• Korean Journal of Materials Research
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• v.11 no.8
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• pp.679-684
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• 2001

The surface of natural graphite has not only good electrical conductivities and lubrication properties but also has strong hydrophobicity. There are no functional groups and chemical properties on it. It is difficult to join with any other ions and to disperse in aqueous system. In order to increase dispersion ability throughout modification of surface property, it is necessary to let graphite have some function on its surface by the adsorption of surfactant molecules. In this study, using zeta potential adsorbed surfactant molecules(ABDM) on graphite surface and its surface Properties turn hydrophobic into hydrophilic. The dispersing mechanism of graphite particles in aqueous system has been explained using the DLVO theory, It is concluded that the high dispersable graphite suspension of which dispersing stability$(T_{1/2})$ is 44.5 hours at pH 10 and 22.5mV zeta potential can be produced.

• BMB Reports
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• v.41 no.5
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• pp.369-375
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• 2008

Polygonatum cyrtonema Lectin (PCL), which is classified as a monocot mannose-binding lectin, has received great regards for its uniquely biological activities and potentially medical applications in cancer cells. This paper was initially aimed to study apoptosis of PCL on Hela cells. Thus, 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) method was carried out. Through observation of cell morphologic changes and Lactate dehydrogenase (LDH) activity-based cytotoxicity assays, PCL induced HeLa cell apoptosis in a dose-dependent manner. To further gain structural basis, multiple alignments, homology modeling and docking experiments were performed to analyze the correlation between its biological activities and mannose-binding sites. Eventually, considering docking data, chemical modification properties on the three mannose-binding sites were analyzed by a series of biological experiments (e.g., hemagglutinating and mitogenic activity assays, fluorescence and Circular Dichrosim (CD) spectroscopy) to profoundly identify the role of some key amino acids in the structure-function relationship of PCL.

• Journal of Korean Foot and Ankle Society
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• v.23 no.3
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• pp.91-99
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• 2019

Purpose: This retrospective study reports the intermediate-term clinical outcomes including the practical function in daily and sports activities after total ankle arthroplasty for end-stage rheumatoid arthritis, as well as the effects of modification of perioperative anti-rheumatic medications. Materials and Methods: Twelve patients were followed for a minimum of 2 years after total ankle replacement for end-stage rheumatoid arthritis. Perioperative anti-rheumatic medications in all patients were modified based on a specific guideline. Clinical evaluations consisted of American Orthopaedic Foot and Ankle Society (AOFAS) scores, Foot and Ankle Outcome Score (FAOS), and Foot and Ankle Ability Measure (FAAM) scores. Periodic radiographic evaluation was conducted to detect changes in ankle alignment and postoperative complications. Results: Mean AOFAS, FAOS, and FAAM scores improved significantly from 37.5 to 81.2, 39.1 to 72.4, and 33.8 to 64.0 points at final follow-up, respectively (p<0.001). Functional outcomes in daily and sports activities at final follow-up were found to be 76.5 and 55.8 points for the FAOS and 70.5 and 57.5 points for the FAAM, respectively. As early postoperative complications, there was one case of local wound necrosis, one case of medial malleolar fracture, and one case of deep peroneal nerve injury. Radiological evaluation revealed two cases of asymptomatic heterotopic ossification and one case of progressive arthritis in the talonavicular joint. Reoperation was performed in only one patient (8.3%) with a medial soft tissue impingement at a mean of 35.6 months follow-up. Conclusion: Total ankle arthroplasty appears to be an effective surgical option for end-stage rheumatoid arthritis. Practical functions in daily and sports activities were significantly improved at intermediate-term follow-up. Modification of perioperative anti-rheumatic medications can be one of the solutions to reduce the postoperative complication rate.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.1C
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• pp.78-85
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• 2007

With the advancement of the digital broadcasting and popularity of the Internet, recently, many studies are making on the digital watermarking for the copyright protection of digital data. This paper proposes the minimum modification method of motion vector to minimize the degradation of video quality, hiding subtitles of many language and information of OST(original sound track), character profiles, etc. as well as the copyright protection. Our proposed algorithm extracts feature vector by comparing motion vector data with watermark data, and minimize the modification of motion vectors by deciding the inversion of bit. Thus the degradation of video quality is minimized comparing to conventional algorithms. This algorithm also can check data integrity, and retrieve embedded hidden data simply and blindly. And our proposed scheme can be useful for conventional MPEG-1, -2 standards without any increment of bit rate in the compressed video domain. The experimental result shows that the proposed scheme obtains better video quality than other previous algorithms by about $0.5{\sim}1.5dB$.

• Korean Journal of Poultry Science
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• v.17 no.3
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• pp.217-223
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• 1990

This study was undertaken to find out the changes of chemically modified egg albumen grl after heat treatment at $95^{\circ}C$ for 30 minutes or at $120^{\circ}C$ for 30 minutes. Acetylation and succinylation increased the hardness of egg albumen gel, it was rather higher at high heat treatment($120^{\circ}C$, 30min.) than at low heat treatment($95^{\circ}C$, 30min). The cohesiveness of egg albumen gel was improved remarkably by succinylation and maleylation at both low and high heat treatment. The lightness and yellowness of egg albumen gel were decreased by chemical modification. Initial heat denaturation temperature of egg albumen was increased by 11$^{\circ}C$ by acetylation, by $12.5^{\circ}C$ by maleylation and by ,$14.5^{\circ}C$ by succinylation.

• BMB Reports
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• v.40 no.5
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• pp.684-689
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• 2007

The endogenous neurotoxin, 1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (salsolinol), has been considered a potential causative factor for the pathogenesis of Parkinson's disease (PD). In the present study, we examined the pattern of human Cu,Zn-superoxide dismutase (SOD) modification elicited by salsolinol. When Cu,Zn-SOD was incubated with salsolinol, some protein fragmentation and some higher molecular weight aggregates were occurred. Salsolinol led to inactivation of Cu,Zn-SOD in a concentration-dependent manner. Free radical scavengers and catalase inhibited the salsolinol-mediated Cu,Zn-SOD modificaiton. Exposure of Cu,Zn-SOD to salsolinol led also to the generation of protein carbonyl compounds. The deoxyribose assay showed that hydroxyl radicals were generated during the oxidation of salsolinol in the presence of Cu,Zn-SOD. Therefore, the results indicate that free radical may play a role in the modification and inactivation of Cu,Zn-SOD by salsolinol.

• Bulletin of the Korean Chemical Society
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• v.32 no.5
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• pp.1471-1474
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• 2011

A series of new polymers containing 1,2,3-triazoles were synthesized and their structures and properties were characterized by FT-IR, $^1H$ NMR, TGA, DSC and GPC. The results showed that the polymers modified by alkyl groups had good solubility, thermal stability and reasonable molecular weights. It was also demonstrated that the properties of fluorine-containing polymers were seriously affected by fluorine atoms with hydrophobic and chemical proof properties.