• Bulletin of the Korean Chemical Society
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• 제25권5호
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• pp.711-714
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• 2004

Peroxynitrite enters erythrocytes through band 3 anion exchanger and oxidizes cytosolic proteins therein. As a protein associated with band 3, carbonic anhydrase II may suffer from peroxynitrite-induced oxidative damages. Esterase activity of carbonic anhydrase II decreased as the concentration of peroxynitrite increased. Neither hydrogen peroxide nor hypochlorite affected the enzyme activity. Inactivation of the enzyme was in parallel with the release of zinc ion, which is a component of the enzyme's active site. SDS-PAGE of peroxynitrite-treated samples showed no indication of fragmentation but non-denaturing PAGE exhibited new bands with lower positive charges. Western analysis demonstrated that nitration of tyrosine residues increased with the peroxynitrite concentration but the sites of nitration could not be determined. Instead MALDI-TOF analysis identified tryptophan-245 as a site of nitration. Such modification of tryptophan residues is responsible for the decrease in tryptophan fluorescence. These results demonstrate that peroxynitrite nitrates tyrosine and tryptophan residues of carbonic anhydrase II without causing fragmentation or dimerization. The peroxynitrite-induced inactivation of the enzyme is primarily due to the release of zinc ion in the enzyme's active site.

• Mass Spectrometry Letters
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• 제7권4호
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• pp.85-90
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• 2016

Post-translational modifications (PTMs) of proteins regulate self-renewal and differentiation in embryonic stem cells (ESCs). Nitration of tyrosine residues of proteins in ESCs modulates their downstream pathways, which can affect self-renewal and differentiation. However, protein tyrosine nitration (PTN) in ESCs has been rarely studied. We reviewed 23 nitrated sites in stem cell proteins. Functional enrichment analysis showed that these nitrated proteins are involved in signal transduction, cell adhesion and migration, and cell proliferation in ESCs. Comparison between the nitrated and known phosphorylated sites revealed that 7 nitrated sites had overlapping phosphorylated sites, indicating functional links of PTNs to their associated signaling pathways in ESCs. Therefore, nitrated proteome provides a basis for understanding potential roles of PTN in self-renewal and differentiation of ESCs.

• 대한화학회지
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• 제58권1호
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• pp.72-75
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• 2014

In the presence of zeolites, 4,4'-dibromobiphenyl could be region-selectively nitrated by the action of nitrogen dioxide and molecular oxygen. The ratio of 4,4'-dibromo-2-nitrobiphenyl to 4,4'-dibromo-3-nitrobiphenyl could reach 14 in a high yield of 90%. Zeolites could be easily regenerated by heating and reused four times to give the results similar to those obtained with fresh catalyst. Compared with the classic nitration method, no nitric acid and sulfuric acid were used, which suggested that the method was an environmentally economic process.

• Bulletin of the Korean Chemical Society
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• 제33권2호
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• pp.373-374
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• 2012

• Bulletin of the Korean Chemical Society
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• 제25권9호
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• pp.1414-1416
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• 2004

• Bulletin of the Korean Chemical Society
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• 제35권3호
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• pp.709-714
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• 2014

Protein tyrosine nitration is considered as an important indicator of nitrosative stresses and as one of the main factors for pathogenesis of inflammation and neuronal degeneration. In this study, we investigated various nitrosative modifications of bovine carbonic anhydrase II (CAII) through qualitative and semi-quantitative analysis using the combined strategy of Fourier transformation ion cyclotron resonance mass spectrometry (FT-ICR MS) and ion-trap tandem mass spectrometry (IT-MS/MS). FT-ICR MS and its spectra were used for the search of the pattern of nitrosative modifications. Identification of nitrosatively modified tyrosine sites were executed through IT-MS/MS. In addition, we also tried to infer the reason for the site-specific nitrosative modifications in CAII. In view of the above purpose, we have explored- i) the side chain accessibility, ii) the electrostatic environment originated from the acidic/basic amino acid residues neighboring to the nitrosatively modified site and iii) the existence of competing amino acid residues for nitration.

• 대한화학회지
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• 제37권2호
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• pp.244-248
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• 1993

니트로 알코올은 브로모 알코올의 치환반응으로 얻었다. 두번째 니트로 원자단은 사슬 길이에 따라 다른 방법으로 도입했다. 3,3-dinitro-1-propanol은 분자내 염기성 니트로화 반응으로 형성되면 5,5-dinitro-1-pentanol은 산화촉매 니트로화 반응으로 얻었다. 3,3-dinitro-1,6-hexanediol과 4,4-dinitro-1,8-octanediol은 3,3-dinitro-1-propanol과 5,5-dinitro-1-pentanol에 acrolein을 가해 Michael 반응으로 알데히드를 얻고 환원하여 합성했다. 치환반응시 알코올 보호기는 아세틸기가 좋으며 산화촉매 니트로 반응에서는 THP 원자단이 좋은 보호기이다.

• 대한화학회지
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• 제45권6호
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• pp.538-545
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• 2001

전자끌게 치환기를 함유하고 있는 몇 가지 대표적인 biphenyl 유도체의 니트로화 반응 생성물의 이성질체 비율을 조사하였다. 이성질체를 분리하여 각각의 $^1H$ NMR을 얻고 이를 근거로 반응 후 생성되는 혼합물의 $^1H$ NMR을 정량적으로 분석함으로서 이성질체의 생성비율을 결정하는 효율적인 방법을 확립하였다. 분리가 어려운 니트로 화합물의 경우 니트로를 아민으로 환원하고, 카르복실기는 에틸 에스테르로 전환하여 분리할 수 있었다. 이성질체의 생성비율을 향상시키기 위하여 몇 가지 대표적인 반응조건에서 니트로화 반응을 수행하였으며 확립된 방법을 이용하여 각 이성질체의 비율을 정확히 결정할 수 있었다. 반응 조건에 따라 또는 치환기의 위치 및 종류에 따라 위치 선택성이 상당히 다른 결과를 보였다.

• 대한한의학회지
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• 제23권4호
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• pp.55-63
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• 2002

Objectives: Peroxynitrite ($ONOO^{-}$), formed from the reaction of superoxide <${\cdot}O_2^{-}$) and nitric oxide (NO), is a cytotoxic species that can oxidize several cellular components such as proteins, lipids and DNA. It has been implicated in diseases such as aging process, Alzheimer's disease, rheumatoid arthritis, cancer and arteriosclerosis. Due to the lack of endogenous enzymes responsible for $ONOO^{-}$ inactivation, developing a specific $ONOO^{-}$ scavenger is of considerable importance. The aim of this study was to evaluate $ONOO^{-}$ scavenging activity and its mechanism in Cheonga-hwan (CAH). Methods: The $ONOO^{-}$ scavenging activity in CAH was assayed by measuring oxidized dihydrorhodamine 123 (DHR 123) by fluorescence. The scavenging efficacy was expressed as $IC_{50}$, showing the concentration of each sample required to cause 50% inhibition of DHR 123 oxidation. In a separate study, the protective effect of CAR on $ONOO^{-}$-induced nitration of bovine serum albumin (BSA) was investigated using immunoassay with a monoclonal anti-nitrotyrosine antibody, and a horseradish peroxidase-conjugated anti-mouse secondary antibody from sheep. Results: CAH showed potent scavenging activities of $ONOO^{-}$, NO and ${\cdot}O_2^{-}$. The data demonstrated that CAH led to decreased $ONOO^{-}$-mediated nitration of tyrosine through electron donation. CAH showed significant inhibition on nitration of bovine serum albumin by $ONOO^{-}$ in a dose-dependent manner. Conclusions: CAH can be developed as an effective peroxynitrite scavenger for the prevention of the $ONOO^{-}$ involved diseases.

• 한국소음진동공학회논문집
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• 제15권11호
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• pp.1223-1231
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• 2005

Recently, the issue of ship nitration due to the large scale, high speed and lightweight of ship is emerging. For pleasantness in the cabin, shipbuilders are asked for strict vibration criteria and the degree of nitration level at a deckhouse became an important condition for taking order from customers. This study proposes a new optimization framework that is NASTRAN external call type optimization method (OptShip) and applies to an optimum design to decrease the nitration level of a deckhouse. The merits of this method are capable of using of global searching method and selecting of various objective function and design variables. The global optimization algorithms used here are random tabu search method which has fast converging speed and searches various size domains and genetic algorithm which searches multi-point solutions and has a good search capability in a complex space. By adapting OptShip to full-scale model, the validity of the suggested method was investigated.