• 공업화학
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• 제3권1호
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• pp.72-80
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• 1992

상이동촉매를 사용하여 Group 6의 $M(CO)_4$(2, 2'-bipyridine)[M=Cr, Mo, W]을 $M(CO)_6$의 CO 리간드를 2개의 비공유 전자쌍 주게인 2, 2'-bipyridine으로 치환하여 합성할 때 촉매의 종류와 용매가 생성물의 수율에 미치는 영향을 고찰하였다. 촉매는 형태, 중심양이온 및 음이온의 종류, 양이온에 결합된 알킬기와 아릴기의 종류, 그리고 사슬길이가 다른 다양한 촉매를 사용하였다.

• Journal of Microbiology and Biotechnology
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• 제26권2호
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• pp.263-269
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• 2016

Temperate phages have been suggested to carry virulence factors and other lysogenic conversion genes that play important roles in pathogenicity. In this study, phage TEM123 in wild-type Staphylococcus aureus from food sources was analyzed with respect to its morphology, genome sequence, and antibiotic resistance conversion ability. Phage TEM123 from a mitomycin C-induced lysate of S. aureus was isolated from foods. Morphological analysis under a transmission electron microscope revealed that it belonged to the family Siphoviridae. The genome of phage TEM123 consisted of a double-stranded DNA of 43,786 bp with a G+C content of 34.06%. A bioinformatics analysis of the phage genome identified 43 putative open reading frames (ORFs). ORF1 encoded a protein that was nearly identical to the metallo-β-lactamase enzymes that degrade β-lactam antibiotics. After transduction to S. aureus with phage TEM123, the metallo-β-lactamase gene was confirmed in the transductant by PCR and sequencing analyses. In a β-lactam antibiotic susceptibility test, the transductant was more highly resistant to β-lactam antibiotics than S. aureus S133. Phage TEM123 might play a role in the transfer of β-lactam antibiotic resistance determinants in S. aureus. Therefore, we suggest that the prophage of S. aureus with its exotoxin is a risk factor for food safety in the food chain through lateral gene transfer.

• 대한의용생체공학회:의공학회지
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• 제30권5호
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• pp.355-361
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• 2009

Mitochondria play a key role in maintaining life by producing ATP and heat. Recent researches have demonstrated that degenerative diseases such as heart failure, obesity/diabetes, cardiovascular disease, and psychiatric diseases are accompanied by mitochondria dysfunction. In this sense, mitochondria medicine considers the significance of mitochondria in human pathology and tries to explain degenerative diseases as a fatal consequence of mitochondria dysfunction. Here, I introduce the fundamentals of mitochondria physiology and present examples showing the relationship between mitochondria dysfunction and chronic complex diseases. Although mitochondria medicine uses a molecular biological approach predominantly, a biomedical engineering approach might play a critical role in unveiling the complexity of mitochondria medicine and in its application to the diagnosis and treatment of chronic diseases. Thus, I also briefly review the prospects of research using biomedical engineering methods.

• 대한의생명과학회지
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• 제9권3호
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• pp.167-170
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• 2003

Cytochrome $b_{5}$($b_{5}$) can be found in a variety of tissues and plays a role in the electron transfer pathways. Several retropseudogenes (numbered as I, II, II, IV, V) have been identified and well investigated for their structures. However, retropseudogene I is not clear in terms of its location on the chromosome. In addition the structure and the exression of retropseudogene V have not been confirmed. To examine the structure of bs retropseudogenes V and to see whether it is expressed in human blood we applied recombinant DNA technologies including polymerase chain reaction (PCR) and DNA sequencing. Retropseudogene V turned out to contain open reading frame (ORF) within its structure, however, no evidence of its expression was detected. Retropseudogene I was also found on the chromosome V. This study should contribute to the understanding of the structure of bs gene family.

• Bulletin of the Korean Chemical Society
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• 제17권2호
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• pp.179-182
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• 1996

Hydrodediazoniation product (3a-d) was found to be the major product in the reaction of arenediazonium tetrafluoroborate (1a-d) with triethylamine (2) in methanol under nitrogen at room temperature. A quantitative study on the title reaction was investigated in detail and two remarks were noteworthy. One was the linear increase in the yield of 3a-d by increasing the molar concentration of 2 until equimolar concentration was reached between 1a-d and 2. The other was the suppression of the formation of 3a-d in the presence of oxygen. Based on these results, the title reaction was better understood by 1:1 electron transfer reaction between reactants (1a-d and 2) rather than by radical chain mechanism proposed in the reaction of arenediazonium tetrafluoroborate and triphenylphosphine.

• 미생물학회지
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• 제30권2호
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• pp.101-107
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• 1992

화학 영양성으로 배양한 Rps. gelatinosa 에서 2회의 시토크롬 c 친화성 크로마토그래피와 DEAE-Sephacel 이온 교환 크로마토그래피 등 3 단계의 크로마토그래피를 수행하여 시토로콤 c 산화효소를 정제하였다. 정제된 시토크롬 c 산화효소는 Sephacryl S-300 에 의한 분자걍이 약 110,000 Da 이고 SDS-gel 전기영동에 의한 분자량이 약 52.000 Da 으로써 이량체일 것으로 보인다. 전제된 시토크롬 c 산화효소는 온도데 매우 불안정하고 말 심장 시토크롬 c 를 기질로 사용했을때 Km 값은 $20\mu$M, Vmax 값은 44unit/mg prot. 이며 pH 6.4 의 효소방응 최적 pH 와 25.deg.C 의 최적 온도를 보였다. 환원된 시토크롬 c 산화효소는 554, 523, 421 nm 에서 .alpha., .betha. soret 흡수대를 보였고 chromatophore 에서와 마찬가지로 KCN 과 $NaN_{3}$ 에 의해서는 효소 활성도가 저해를 받았지만 CO 와 antimycin A, myxothiazol 에 의해서는 효소 활성도가 저해를 받지 않았다. 빛을 에너지원으로 배양하거나 또는 화학영양성으로 배양하든지 모두 시토크롬 c-551 이 생성되었고 환원된 시토크롬 c-551 은 시토크롬 c 산화효소에 의해 산화되었다. 시토크롬 c-551 을 기질고 이용하였을 때 시토크롬 c 산화효소의 Km 값은 $26\mu$M 이었고 Vmax 값은 31.unit./mg prot. 로써 말심장의 시토크롬 c 를 기질로 이용할때 보다 오히려 낮았다. 이와 같은 결과로 보아 화학 영양성은 배양한 Rhodopseudomonas gelatinosa 에서 호흡에 의한 전자전달은 시토크롬 c-551 이 시토크롬 $bc_{1}$ 복합체로 부터 전자를 받아 b-형 시토크롬 c 산화효소에 전자를 전달해 주고 최정적으로 산소를 환원시킬 것으로 생각된다.

• Applied Microscopy
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• 제38권2호
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• pp.125-133
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• 2008

Mitochondria 내막의 cytochrome-c-oxidase는 세포의 에너지 생합성에 중요한 요소이며, 세포자멸사와 각종세포의 병리학적 현상과 밀접한 연관성이 있는 전자전달계효소로 알려져 있다. Porin 단백은 mitochondria 내막과 외막에 분포하는 효소단백으로 전자전달계효소 형성과 ATP 운반에 관여하는 것으로 알려져 있다. 따라서 면역현미경법을 사용하여 cytochrome-c-oxidase의 분포와 porin 단백과의 연관성을 확인하여 mitochondria의 cristae에 분포하는 cytochrome-c-oxidase의 형성과 변화를 알아보고자 하였다. Cardiac muscle tissue의 sarcoplasm에는 많은 수의 mitochondria가 분포하며, cytochrome-c-oxidase가 풍부한 mitochondria와 porin 단백이 풍부한 mitochondria로 구별되었다. Cytochrome-c-oxidase가 풍부한 mitochondria는 porin 단백이 빈약하고 porin 단백이 풍부한 mitochondria는 cytochrome-c-oxidase가 소량 포함되어 있는 것으로 관찰되었다. 심근조직의 부위에 따라 근형질에 분포하는 mitochondria에 cytochrome-c-oxidase가 풍부한 mitochondria와 porin 단백이 풍부한 mitochondria가 각각 상이하게 분포하였다. 이상의 결과로 미성숙 mitochondria는 많은 양의 porin 단백을 함유하여 근형질로부터 단백질 소단위를 mitochondria 막내로 운반하여 cytochrome-c-oxidase를 형성시키고 mitochondria가 성숙하면서 ATP를 운반할 최소한 양의 porin 단백만을 남기고 소멸되는 것으로 추측된다.

• Composites Research
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• 제29권4호
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• pp.173-178
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• 2016

Graphene oxide (GO) was concurrently reduced and functionalized using long alkyl chain dodecyl amine (DA). The DA functionalized GO (DA-G) was assumed to disperse homogenously in linear low density polyethylene (LLDPE). Subsequently, DA-G was used to fabricate DA-G/LLDPE composites by melt mixing technique. Fourier transform infrared spectra analysis was performed to ascertain the simultaneous reduction and functionlization of GO. Field emission scanning electron microscopy analysis was performed to ensure the homogenous distribution and dispersion of DA-G in LLDPE matrix. The enhanced storage modulus value of the composites validates the homogenous dispersion of DA-G and its good interfacial interaction with LLDPE matrix. An increased in tensile strength value by ~ 64% also confirms the generation of good interface between the two constituents, through which efficient load transfer is possible. However, no significant improvement in glass transition temperature was observed. This simple technique of fabricating LLDPE composites following industrially viable melt mixing procedure could be realizable to developed mechanically strong graphene based LLDPE composites for future applications.

• Journal of Microbiology and Biotechnology
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• 제30권5호
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• pp.777-784
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• 2020

Self-sufficient P450s, due to their fused nature, are the most effective tools for electron transfer to activate C-H bonds. They catalyze the oxygenation of fatty acids at different omega positions. Here, two new, self-sufficient cytochrome P450s, named 'CYP102A15 and CYP102A170,' from polar Bacillus sp. PAMC 25034 and Paenibacillus sp. PAMC 22724,respectively, were cloned and expressed in E. coli. The genes are homologues of CYP102A1 from Bacillus megaterium. They catalyzed the hydroxylation of both saturated and unsaturated fatty acids ranging in length from C₁₂-C₂₀, with a moderately diverse profile compared to other members of the CYP102A subfamily. CYP102A15 exhibited the highest activity toward linoleic acid with K_m 15.3 μM, and CYP102A170 showed higher activity toward myristic acid with Km 17.4 μM. CYP10A170 also hydroxylated the Eicosapentaenoic acid at ω-1 position only. Various kinetic parameters of both monooxygenases were also determined.

• Bulletin of the Korean Chemical Society
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• 제15권2호
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• pp.154-161
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• 1994

Studies have been conducted to explore single electron transfer (SET) induced photocyclization reactions of N-(trimethylsilylmethylthioalkyl)phthalimides (alkyl=ethyl, n-propyl, n-butyl, n-pentyl, and n-hexyl). Photocyclizations occur in methanol in modest to high yields to produce cyclized products in which phthalimide carbonyl carbon is bonded to the carbon of side chain in place of the trimethylsilyl group. Mechanism for these photocyclizations involving intramolecular SET from sulfur in the ${\alpha}$-silylmethylthioalkyl groups to the singlet excited state phthalimide moieties followed by desilylation of the intermediate ${\alpha}$ -silylmethylthio cation radicals and cyclization by radical coupling is proposed. In contrast, photoreactions of N-(trimethylsilylmethylthioalkyl)phthalimides in acetone follow different reaction routes to produce another cyclized products in which carbon-carbon bond formation takes place between the phthalimide carbonyl carbon and the carbon ${\alpha}$ to silicon and sulfur atoms via triplet carbonyl hydrogen abstraction pathway. The normal singlet SET pathway dominates this triplet process for photoreactions of these substances in methanol while the triplet process dominates the singlet SET pathway for those in acetone. The efficient and regioselective cyclization reactions observed for photolyses in methanol represent synthetically useful processes for construction of medium and large ring heterocyclic compounds.