• 대한화학회지
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• 제12권3호
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• pp.121-127
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• 1968

In the oligomerization of p-aminophenol under the catalytic action of the metallic complexes, the effects of the ligands are studied. When the initial velocity of $O_2$ uptake at pH 8 using Fe(Ⅲ) as the central metal and N-hydroxylethylethylenediaminetriacetic acid (HEDTA), ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), 1,2-cyclohexanediaminetetraacetic acid(CyDTA) as the ligands respectively are compared, the velocities are as the following order: HEDTA > EDTA > DTPA > CyDTA. Further when the effect of the ligands, nitrilotriacetic acid (NTA), HEDTA, EDTA, and DTPA, on the yields of oligomers are compared, the result shows as the following order: NTA > HEDTA > EDTA > DTPA. These are nearly reverse order of the stability constants of the complexes. In order to determine the composition of the mixed complexes at the initial step, the method of continuous variation is used, and it is found that the composition ratio of Fe-EDTA complex to monomer in the mixed complexes is one at pH 5-8 range. It is also found that at pH 9 or in the more alkaline range, side reactions occur to form water soluble dimer of quinone type and the catalytic action of the metallic complex markedly decreases on account of the hydrolysis of the central metal by the $OH^-$ ion.

• Journal of Microbiology
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• 제40권2호
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• pp.129-133
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• 2002

The fungus, Emericellopsis minima W2, capable of degrading poly(3-hydroxybutyrate) (PHB) was isolated from a waste water sample. Production of the PHB depolymerase from E. minima W2 (PhaZ/ sub Emi/) was significantly repressed in the presence of glucose. PhaZ/ sub Emi/ was purified by column chromatography on Octyl-Sepharose CL-4B and Sephadex G-100. The molecular mass of the PhaZ/ sub Emi/), which consisted of a single polypeptide chain, was estimated to be 48.0 kDa by SDS-PAGE and its pI vague was 4.4. The maximum activity of the PhaZ/ sub Emi/ was observed at pH 9.0 and 55$\^{C}$. It was significantly inactivated by 1mM dithiothreitol, 2mM diisopropyl fluorphosphate, 0.1mM Tween 80, and 0.1 mM Triton X-l00, but insensitive to phenylmethylsulfonyl fluoride and N-ethylmaleimide. The PhaZ/ sub Emi/ efficiently hydrolyzed PHB and its copolyester with 30 mol% 3-hydroxyvalerate, but did not act on poly(3-hydroxyoctanoate). It also hydrolyzed p-nitrophenylacetate and p-nitrophenylbutyrate but hardly affected the longer-chain forms. The main hydrolysis product of PHB was identified as a dimer of 3-hydroxybutyrate.

• Toxicological Research
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• 제35권2호
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• pp.161-165
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• 2019

Cysteamine has been used in cosmetics as an antioxidant, a hair straightening agent, and a hair waving agent. However, recent studies indicate that cysteamine can act as an allergen to hairdressers. The objective of this study was to develop and validate a simple and effective reversed-phase high-performance liquid chromatography (RP-HPLC) method for the measurement of cysteamine and its dimer, cystamine. Sodium 1-heptanesulfonate (NaHpSO) was used as an ion-pairing agent to improve chromatographic performance. Separation was performed on a Gemini C18 column ($250mm{\times}4.6mm$, $5{\mu}m$ particle size) using a mobile phase composed of 85:15 (v/v) 4 mM NaHpSO in 0.1% phosphoric acid:acetonitrile. UV absorbance was monitored at 215 nm. The RP-HPLC method developed in this study was validated for specificity, linearity, limit of detection, limit of quantitation, precision, accuracy, and recovery. Cysteamine and cystamine were chromatographically resolved from other reducing agents such as thioglycolic acid and cysteine. Extraction using water and chloroform resulted in the recovery for cysteamine and cystamine ranging from 100.2-102.7% and 90.6-98.7%, respectively. This validated RP-HPLC method would be useful for quality control and monitoring of cysteamine and cystamine in cosmetics.

• Journal of Photoscience
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• 제9권2호
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• pp.439-441
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• 2002

Cyanobacteria are the dominant micro flora in rice-fields, contributing significantly to fertility as a natural biofertilizer. Recent studies show a continuous depletion of the stratospheric ozone layer, and the consequent increase in solar UV-B (280-315 nm) radiation reaching the Earth's surface. UV-B radiation causes reduction in growth, survival, protein content, heterocyst frequency and fixation of carbon and nitrogen in many cyanobacteria. UV -B induced bleaching of pigments, disassembly of phycobilisomal complexes, thymine dimer formation and alterations in membrane permeability have also been encounterd in a number of cyanobacteria. However, certain cyanobacteria produce photoprotective compounds such as water soluble colorless mycosporine-like amino acids (MAAs) and the lipid soluble yellow-brown colored sheath pigment, scytonemin, to counteract the damaging effects of UV-B. Cyanobacteria, such as Anabaena sp., Nostoc commune, Scytonema sp. and Lyngbya sp. were isolated from rice fields and other habitats in India and screened for the presence of photoprotective compounds. A circadian induction of the synthesis of MAAs by UV -B was noted in a number of cyanobacteria. Polychromatic action spectra for the induction of MAAs in Anabaena sp. and Nostoc commune also show the induction to be UV-B dependent peaking at 290 nm. Another photoprotective compound, scytonemin, with an absorption maximum at 386 nm (also absorbs at 300, 278, 252 and 212 nm), was detected in many cyanobacteria. In conclusion, a particular cyanobacterium having photoprotective compounds may be a potent candidate as biofertilizer for crop plants.

• 대한화학회지
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• 제29권5호
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• pp.510-515
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• 1985

진한 메탄설폰산(약10M)에서 초록색의 $MoO_{(aq)}^{3+}$는 진한 초록색의 이합체인$Mo_2O_2(OH)_{2(aq)}^{4+}$를 생성한다. 또한 이러한 진한 초록색은 15-16M의 메탄설폰산에서 존재하는 $MoO_{(aq)}^{3+}$용액에 물을 가하면 나타나며 15M의 메탄설폰산에서 단위체의 몰흡광계수는 415nm에서 약 20이다. 속도 상수는 이 실험조건하에서 아쿠오몰리브덴(V)와 수소이온농도에 의존하지 않는다. $Mo_2O_2(OH)_{2(aq)}^{4+}$의 수산화이온은 HPTS 약 6M, $CH_3SO_3H$는 10M이하에서 탈수소화반응이 일어난다. 마지막 생성물의 말단산소와 다리산소의 구조는 (*image) 단위를 가진 것으로 확인되었다.

• 한국식품과학회지
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• 제37권3호
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• pp.364-371
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• 2005

개발된 항균 포장 원지를 이용하여 포장 봉지(packaging bag)와 골판지 포장 상자(corrugated box)를 제작하였고, 여기에 과채류를 포장하였을 때 일반 포장 봉지나 골판지 상자에서 포장된 과채류 보다 변패 미생물의 발생이나 생체중 감소가 상당히 줄어들었다. 이는 BAAG에 의해 과채류의 변패에 관여하는 미생물의 생육을 차단하였고, 제올라이트에 의해 과채류의 조직을 빠르게 연화시키는 기체들인 에틸렌가스, 이산화탄소 및 산소가 제거되었으며, AKD에 의해 과채류가 보유한 수분 손실을 최소한으로 일어나게 하였기 때문이다. 결론적으로 BAAG, 제올라이트, 그리고 AKD로 처리된 포장 원지를 이용하여 제작한 포장대(packaging bag)과 골판지 포장 상자는 저장 과채류의 선도를 유지하는 데 탁월한 효과를 발휘하였고, 기능성 첨가제의 처리로 인한 제조 원가의 상승은 폐기 과채류의 양이 감소하면서 상쇄시킬 수 있었다. 따라서 일반 골판지 상자에 저장된 과채류보다는 기능성 골판지 상자에 저장하는 방법이 보다 경제적인 저장 방법이 될 수 있음을 확인하였다.

• 한국응용과학기술학회지
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• 제29권3호
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• pp.531-542
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• 2012

본 논문은 바이오폴리우레탄의 연구동향에 관한 것이다. 바이오폴리우레탄은 원료 중의 식물유 폴리올과 이소시아네이트의 중부가 고분자이다. 피마자유의 주성분은 히드록시기를 갖는 리시놀산의 트리글리세라이드이다. 이외의 히드록시기가 없는 식물유는 이중결합 위치에서 에폭시화 후 고리열림, 히드로포르밀화 후 수소첨가, 가오존분해 후 수소첨가, 티올-엔 반응으로 히드록시기를 부여한다. 폴리올의 반응성 및 마이크로도메인의 모폴로지 조절을 위한 하이퍼브랜치 폴리올, 일차 알코올 폴리올, 다당류 폴리올이 있다. 의료용의 생분해성 폴리락트산 폴리올, 가수분해 방지용 지방산 다이머 폴리올, 이온성 기를 함유한 수 분산 폴리우레탄용 폴리올이 있다. 바이오폴리올을 이용한 바이오폴리우레탄은 경질 및 연질 폼, 코팅제, 접착제, 실런트, 엘라스토머에 쓰인다.

• Asian-Australasian Journal of Animal Sciences
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• 제17권11호
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• pp.1591-1598
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• 2004

To isolate the $\beta$-galactosidase producing thermophilic bacteria, samples of mud and water were collected from hot springs of avolcanic area near Golden Springs in New Zealand. Among eleven isolated strains, the strain of KNOUC112 produced the highest amounts of $\beta$-galactosidase at 40 h incubation time (0.013 unit). This strain was aerobic, asporogenic bacilli, immobile, gram negative, catalase positive, oxidase positive, and pigment producing. Optimum growth was at 70-72$^{\circ}C$, pH 7.0-7.2, and it could grow in the presence of 3% NaCl. The main fatty acids of cell components were iso-15:0 (30.26%), and iso-17:0 (31.31%). Based on morphological and biochemical properties and fatty acid composition, the strain could be identified as genus Thermus, and finally as Thermus thermophilus by phylogenetic analysis based on 16S rRNA sequence. So the strain is designated as Thermus thermophilus KNOUC112. A gene from Thermus thermophilus KNOUC112 encoding $\beta$-galactosidase was amplified by PCR using redundancy primers prepared based on the structure of $\beta$-galactosidase gene of Thermus sp. A4 and Thermus sp. strain T2, cloned and expressed in E. coli JM109 DE3. The gene of Thermus thermophilus KNOUC112 $\beta$-galactosidase(KNOUC112$\beta$-gal) consisted of a 1,938 bp open reading frame, encoding a protein of 73 kDa that was composed of 645 amino acids. KNOUC112$\beta$-gal was expressed as dimer and trimer in E. coli JM109 (DE3) via pET-5b.

• Molecules and Cells
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• 제39권3호
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• pp.242-249
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• 2016

A balance between production and degradation of reactive oxygen species (ROS) is critical for maintaining cellular homeostasis. Increased levels of ROS during oxidative stress are associated with disease conditions. Antioxidant enzymes, such as extracellular superoxide dismutase (EC-SOD), in the extracellular matrix (ECM) neutralize the toxicity of superoxide. Recent studies have emphasized the importance of EC-SOD in protecting the brain, lungs, and other tissues from oxidative stress. Therefore, EC-SOD would be an excellent therapeutic drug for treatment of diseases caused by oxidative stress. We cloned both the full length (residues 1-240) and truncated (residues 19-240) forms of human EC-SOD (hEC-SOD) into the donor plasmid pFastBacHTb. After transposition, the bacmid was transfected into the Sf9-baculovirus expression system and the expressed hEC-SOD purified using FLAG-tag. Western blot analysis revealed that hEC-SOD is present both as a monomer (33 kDa) and a dimer (66 kDa), as detected by the FLAG antibody. A water-soluble tetrazolium (WST-1) assay showed that both full length and truncated hEC-SOD proteins were enzymatically active. We showed that a potent superoxide dismutase inhibitor, diethyldithiocarbamate (DDC), inhibits hEC-SOD activity.

• 미생물학회지
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• 제55권1호
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• pp.9-16
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• 2019

다양한 미생물은 세포와 주변의 과산화를 방지하고 여분의 에너지를 보관하기 위해 ${\alpha}$-acetolactate decarboxylase(ALDC)를 이용해 아세토인을 생성한다. 아세토인은 안전한 식품 향미 개선제이기 때문에 ALDC를 이용한 아세토인 생합성에 많은 산업체가 관심을 가지고 있다. ALDC는 ${\alpha}$-acetolactate의 탈카르복실화 반응을 통해 아세토인을 생산하는 금속 의존 효소이다. 본 논문에서는 고초균 아종 spizizenii의 ALDC(bssALDC) 결정구조를 $1.7{\AA}$ 해상도에서 보고한다. bssALDC는 두 개의 ${\beta}$-sheet가 중앙부를 형성하는 ${\alpha}/{\beta}$ 구조를 가진다. bssALDC는 중앙부의 소수성 상호작용과 주변부의 친수성 상호작용을 통해 이합체를 형성한다. bssALDC는 세 개의 histidine 잔기와 세 개의 물 분자를 이용해 아연 이온에 배위결합한다. 구조와 서열의 비교 분석에 기초하여 아연 이온과 이 주변부 bssALDC 잔기들이 bssALDC의 효소 활성부위임을 제안한다.