• 한국염색가공학회지
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• 제13권5호
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• pp.312-319
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• 2001

Kinetics and mechanism for alkaline hydrolysis of C. I. Disperse Blue 79(B-79) which is 4-N, N- diacetoxyethyl -2- acylamino-5-ethos y -2'-bromo-4',6'-dinitroazobenzene were investigated. The color strength of B-79 in acetone/water solutions of various NaOH concentrations decreased continuously. The hydrolysis rate of B-79 increased with increasing alkali concentration and appeared following first order reaction. The observed rate constants for various concentrations of B-79 showed similar values, and B-79 was hydrolyzed by first order reaction for dye concentration. Therefore, it was confirmed that the overall reaction follow second order kinetics and proceed via $S_N2$ reaction. From the study on kinetics and spectrometric analysis, it was proposed that the rate determining step of the hydrolysis reaction of B-79 is the nucleophilic substitution reaction - that is the reaction of the rapid attack of OH- on the carbon atom, which is in acceptor ring, adjacent to auto group to break the C-N bond. And it was also found that the final hydrolysis products of B-79 include both the acceptor ring in the form of sodium salt and the donor ring possessing 4-N,N-dihydroxyethyl group converted from 4-N, N-diacetoxyethyl group.

• Mass Spectrometry Letters
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• 제3권1호
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• pp.25-28
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• 2012

Paint Spray is developed as a direct sampling ionisation method for mass spectrometric analysis of additives in polymer-based surface coatings. The technique simply involves applying an external high voltage (5 kV) to the wetted sample placed in front of the mass spectrometer inlet and represents a much simpler ionisation technique compared to those currently available. The capabilities of Paint Spray are demonstrated herein with the detection of four commercially available hindered amine light stabilisers; TINUVIN${(R)}$770, TINUVIN${(R)}$292, TINUVIN${(R)}$123 and TINUVIN${(R)}$152 directly from thermoset polyester-based coil coatings. Paint Spray requires no sample preparation or pre-treatment and combined with its simplicity requiring no specialised equipment makes it ideal for use by non-specialists. The application of Paint Spray for industrial use has significant potential as sample collection from a coil coating production line and Paint Spray ionisation could enable fast quality control screening at high sensitivity.

• Journal of the Korean Wood Science and Technology
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• 제34권6호
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• pp.51-60
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• 2006

가래나무 수피를 채취하여 건조시킨 후 분말로 제조하고 3.2 kg을 아세톤-물(7:3, v/v) 혼합용액으로 추출하여 유기용매를 제거한 후 헥산, 메틸렌클로라이드, 에틸아세테이트 및 물을 사용하여 네 개로 분획하고 에틸아세테이트 및 수용성 분획물에 대하여 칼럼 크로마토그래피를 수행하였으며 용리용매로는 메탄올 수용액과 에탄올-헥산 혼합액을 사용하였다. 그 결과 flavanol 화합물인 pinobanksin, taxifolin 및 ampelopsin, flavonol 화합물인 kaempferol, quercetin 및 myricetin 과 flavone glycoside 화합물인 afzelin, astragalin, quercitrin, isoquercitrin 및 myricitrin을 단리하였으며 NMR 및 MS 스펙트럼을 이용하여 구조를 결정하였다.

• Journal of Microbiology
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• 제40권4호
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• pp.331-334
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• 2002

The substance 0116p, which exhibits cytotoxicity against human macrophage cell line THP-1, was isolated from a mycelial extract of Streptomyces scabiei subsp. chosunensis M0137. The cytotoxic substance was purified by Diaion-HP2O adsorption, solvent extraction, Sephadex LH-20 column chromatography, and silica-gel column chromatography. The molecular formula is C$\_$19/H$\_$38/O$\_$2/ (MW301.10) based on elemental and spectrometric analysis. It was identified as nonadecanoic acid by NMR spectral data. It exhibits cytotoxic activities in various human cancer cell lines, including A549, SK-OV-3, SK-MEL-2 and HCT-15. In addition, 0116p also inhibits IL-12 production in lipopolysaccharide-activated macrophages.

• 한국자기공명학회논문지
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• 제10권1호
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• pp.115-125
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• 2006

Hippuryl-L-histidyl-L-leucine(HHL) is widely used as a substrate of angiotensin converting enzyme(ACE) cleaving the neurotransmitter angiotensin(I) to the octapeptide angiotensin(II). The structure of the substrate molecules should provide information regarding the geometric requirements of the ACE active site. For the purpose of determination of in vivo reaction, metallo(Cu, Zn)-HHL complexes were synthesized and the degree of complex formation were identified by MALDITOF, ESI mass spectrometric analysis. Tn addition, the pH-dependent species distribution curves were obtained by potentiometric titration. Nitrogen atoms of imidazole ring and oxygen atom of caboxylate groups in the peptide chain were observed to be participated in the metal complex formation. After purification of complexes further structural characterization were made by utilizing UV-Vis, electrochemical methods and NMR. Complete NMR signal assignments were carried out by using 2D-spectrum techniques COSY, TOCSY, NOESY, HETCOR. A complex that two imidazole and carboxylate groups are asymmetrically participating to coordination mode was predicted to the solution-state structure of $Cu(II)-HHL_2$ based on $^{13}C-NMR$ signal assignment and NOE information.

• BMB Reports
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• 제44권9호
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• pp.584-589
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• 2011

The mammalian ste20-like kinase (MST) pathway is important in the regulation of apoptosis and cell cycle and emerges as a novel tumor suppressor pathway. MST-induced phosphorylation of Salvador homolog 1 (SAV1), which is a scaffold protein, has not been evaluated in detail. We performed a mass spectrometric analysis of the SAV1 protein that was co-expressed with MST2. Phosphorylation was detected at Thr-26, Ser-27, Ser-36 and Ser-269. Although single or double mutations had little effects, the mutation of all four residues in SAV1 to Ala (SAV1-4A) had inhibitory effects on the MST pathway. MST2-mediated induction of SAV1-4A protein levels, SAV1-4A interaction with MST2 and the self-dimerization of SAV1-4A were weaker compared to those of wild-type SAV1. SAV1-4A inhibited MST2- and K-RasG12V-induced cell death of MCF7 cells. These results suggest that MST-mediated phosphorylation of four residues within SAV1 may be important in the induction of cell death by the MST pathway.

• Natural Product Sciences
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• 제22권4호
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• pp.225-230
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• 2016

Phytochemical investigation from the stem bark of Beilschmiedia pulverulenta resulted in the isolation of five lignans, (+)-yangambin (1), (+)-sesartemin (2), (+)-excelsin (3), (+)-sesamin (4), and (+)-syringaresinol (5), together with lupeol (6), lupenone (7), ${\beta}-sitosterol$ (8), and ${\beta}-sitostenone$ (9). Their structures were established by the analysis of their spectroscopic (1D and 2D NMR) and spectrometric (MS) data, as well as by comparison with those reported in the literature. The isolated lignans were tested for their anticholinesterase (AChE: acetylcholine esterase and BChE: butyryl cholineesterase) and anti-inflammatory (COX-2: cyclooxygenase-2 and LOX: lipoxygenase) activities. All the isolated lignans (1 - 5) exhibited significant inhibition activities in AChE/BChE and COX-2/LOX assays with $IC_{50}$ values ranging from $168.8-504.2{\mu}M$ and $21.0-59.4{\mu}M$, respectively.

• Journal of Microbiology and Biotechnology
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• 제27권6호
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• pp.1150-1156
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• 2017

Understanding phosphorus metabolism in photosynthetic organisms is important as it is closely associated with enhanced crop productivity and pollution management for natural ecosystems (e.g., algal blooming). Accordingly, we exploited highly time-resolved metabolic responses to different levels of phosphate deprivation in Chlamydomonas reinhardtii, a photosynthetic model organism. We conducted non-targeted primary metabolite profiling using gas-chromatography time-of-flight mass spectrometric analysis. Primarily, we systematically identified main contributors to degree-wise responses corresponding to the levels of phosphate deprivation. Additionally, we systematically characterized the metabolite sets specific to different phosphate conditions and their interactions with culture time. Among them were various types of fatty acids that were most dynamically modulated by the phosphate availability and culture time in addition to phosphorylated compounds.

• 약학회지
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• 제59권3호
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• pp.113-119
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• 2015

Protein phosphorylation is one of most important post-translational modifications (PTMs) and plays an important role in regulation of protein function. Here we develop a method for a global identification of phosphopeptides and phosphorylation sites using nano-LC MS/MS. We compared two separation methods, C4 and strong cation ion exchange (SCX). Before phosphopeptides enrichment with $TiO_2$, total proteins from Rat 1 cells have been separated using C4 column or tryptic peptides of proteins from the cells have been separated using SCX column. Finally, we have detected 52 phosphorylation sites on 41 proteins from SCX method and 375 phosphorylation sites on 252 proteins from C4 method, and determined the function and localization of identified phosphoproteins using DAVID software. In particular, we showed new phosphorylation sites from membrane proteins related to various cell signaling mechanisms. This method may contribute to study global signal networks induced by various signals including ligands and drugs.

• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3659-3664
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• 2013

Eight representative explosives (ammonium perchlorate (AP), ammonium nitrate (AN), trinitrotoluene (TNT), 2,4-dinitrotoluene (DNT), cyclonite (RDX), cyclotetramethylenetetranitramine (HMX), pentaerythritol tetranitrate (PETN), and hexanitrostilbene (HNS)) were comprehensively analyzed with an ion trap mass spectrometer in negative ion mode using direct infusion electrospray ionization. MS/MS experiments were performed to generate fragment ions from the major parent ion of each explosive. Explosives in salt forms such as AP or AN provided cluster parent ions with their own anions. Explosives with an aromatic ring were observed as either $[M-H]^-$ for TNT and DNT or $[M]^{{\cdot}-}$ for HNS, while explosives without an aromatic ring such as RDX, HMX, and PETN were detected as an adduct ion with a formate anion, i.e., $[M+HCOO]^-$. These findings provide a guideline for the rapid and accurate detection of explosives once portable MS instruments become more readily available.