• BMB Reports
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• 제33권2호
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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.

• 한국식품영양학회지
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• 제13권4호
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• pp.342-347
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• 2000

과요오드산-산화전분으로 보리 $\beta$-amylase(Bio-zyme ML, 일본 아마노제약)를 변형시켜서 인공당단백질을 만들었다. pH 8.0에서 변형한 효소는 비변형효소의 92%, pH 9.7에서 변형한 효소는 42%의 활성이 남았다. 6$0^{\circ}C$에서의 열안정성은 $\alpha$-cyclodextrin ( $\alpha$-CD) 존재 시에 변형하여 $\alpha$-CD존재시 분석한 효소는 10분 뒤에 비활성의 8%가 남은 반면 변형하지 않은 효소는 4.5%밖에 남지 않았다. pH안정성은 변형 시켜서 $\alpha$-CD존재 하에 분석한 효소가 가장 높아서 pH 2~5와 7~12에서 안정성이 매우 증가하였다. HPLC분석 결과 효소는 두 개의 피크를 나타냈으며 변형시킨 것은 당결합으로 분자량이 커져서 유출시간이 약간 빨라졌다.

• Elastomers and Composites
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• 제42권2호
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• pp.75-85
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• 2007

본 연구에서는 폴리에스터 코드와 고무 매트릭스간의 접착을 향상시키기 위한 접착시스템에 관해 조사하였다. 폴리에스터 코드의 표면 활성화를 통해 접착력을 증진시키기 위해 0.03, 0.05, 0.1, 0.2, 0.5, 1 및 5 wt.％ NaOH 용액으로 폴리에스터 코드를 개질하였다. 개질된 폴리에스터 코드와 결합제가 직접블렌딩된 SBR 고무혼합물과의 접착력을 평가한 결과 0.05 wt.％의 NaOH 농도에서 10분 개질 할 때 최대의 접착강도를 나타내었다. 1 wt.％ 이상의 NaOH 농도에서는 과도한 개질로 인한 폴리에스터 코드의 손상으로 인하여 접착력 실험 동안 코드의 파괴가 발생하였다. 또한, 개질한 폴리에스터 코드에 triallylcyanurate(TC) 접착제를 코팅한 후 상온에서 건조하여 접착시키는 경우 보다 $220^{\circ}C$의 고온에서 건조한 후 고무 매트릭스와 접착시킬 경우 가장 우수한 접착력을 나타내었다.

• 한국재료학회지
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• 제11권8호
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• pp.679-684
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• 2001

천연흑연은 단위구조가 탄소육각망평면이 평행하게 배열된 층상으로 전기전도도 및 윤활성이 우수하나 소수성이 매우 강하며, 표면화학적 목성이 거의 없기 때문에 다른 물질과 흡착이 쉽게 일어나지 않아 분산이 매우 어려운 물질이다. 따라서 본 연구에서는 제타전위를 이용하여 흑연에 ABDM을 흡착시켜 표면특성을 소수성에서 친수성으로 변화시키고 수중현탁액 중에서 흑연입자의 분산 메커니즘을 DLVO이론을 이용하여 설명하였다. 흑연의 제타전위가 22.5mV가 되도록 ABDM의 흡착량 (20mg/g) 및 조건 (PH 10에서 12시간 흡착)을 만족시키면 분산안정성 (T$_{1/2}$) 이 44.5시간인 고분산성 흑연 현탁액을 제조할 수 있다.

• BMB Reports
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• 제41권5호
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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.

• 대한족부족관절학회지
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• 제23권3호
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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.

• 한국통신학회논문지
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• 제32권1C호
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• pp.78-85
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• 2007

최근 디지털 방송의 발달과 인터넷 보급으로 인해 디지털 데이터의 저작권 보호를 위한 디지털 워터마킹에 관한 많은 연구가 이루어지고 있다. 본 논문에서는 저작권 보호 뿐만 아니라 자막이나 인물 소개, 배경 음악에 대한 정보 등 유용한 정보를 은닉하면서 화질 열화를 최소화하기 위하여 움직임벡터의 변경 최소화 기법을 제안한다. 제안한 방법은 매크로블록에서 구한 정보와 워터마크 정보를 비교하여 특성 벡터를 추출하고, 이에 따라 비트의 반전 여부를 결정함으로써 움직임 벡터의 변경을 최소화한다. 따라서 기존의 움직임벡터 기반의 비디오 워터마킹기법에 비해 화질 열화가 최소화될 수 있다. 또한 삽입 정보에 대한 무결성을 제공하며, 워터마크를 매우 간단히 검출할 수 있고, 원 영상이 필요없는 블라인드 워터마킹이 가능하다. 그리고 기존의 비디오 스트림의 형식이 변경되지 않으므로 기존의 MPEG-1, -2 표준과 호환성이 뛰어나다. 본 논문은 실험 결과 기존의 방법에 비해 $0.5{\sim}1.5dB$ 화질이 향상됨을 확인할 수 있었다.

• 한국가금학회지
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• 제17권3호
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• pp.217-223
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• 1990

화학변형에 의해 난백의 열안정성을 증진시키기 위하여 acetic anhdride, succinic anhydrice 및 maleic anhydride 등을 사용하여 화학변형 된 난백친의 열처리 조건에 따른 특성을 검토하였다. 난백겔의 경도는 acetylatiorl과 succinylation에 의해 증가되었으며 고온처리의 경우($120^{\circ}C$, 30분)의 경우가 저온처리의 경우($95^{\circ}C$. 30분)보다 높은 값을 나타내었다. 응집성은 succinylation과 maleylation에 의해 증가되었으며 고온처리 시에는 화학변화에 의해서 모두 증가되었다, 난백겔의 명도( L value)는 maleylation에 의해 크게 감소하였으며 황색도( b value)는 화학변형에 의해 전반적으로 감소하였다. 난백의 초기 열변성온도는 acetylation에 의해 11$^{\circ}C$, maleylation에 의해 $12.5^{\circ}C$ 그리고 sucinylation에 의해 $14.5^{\circ}C$씩 증가하였다.

• BMB Reports
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• 제40권5호
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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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• 제32권5호
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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.