• Elastomers and Composites
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• 제41권1호
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• pp.57-62
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• 2006

1,2-dichlorobenzene 용액에서 풀러렌$[C_{60}]$과 3-chloroperoxy benzoic acid 의 반응을 고분해능 초음파 분광기를 사용하여 조사하였다. 또한 1,2-dichlorobenzene 용액에서 풀러렌$[C_{60}]$과 3-chloroperoxy benzoic acid의 반응 생성물을 MALDI-TOF-MS를 가지고 확인하였다.

• 대한의생명과학회지
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• 제24권2호
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• pp.108-115
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• 2018

In the present study, results of the identification of Gram-positive bacilli (GPB) were analyzed by using the MALDI-TOF MS technique to score each 2-year blood culture at a university hospital. In addition, 16S rRNA sequence analyses and MALDI-TOF MS results are compared to targeting strains that had been isolated two or more times within the same patient, to evaluate the usefulness of MALDI-TOF MS in GPB identification. According to the cut-off (${\geq}1.7$) criteria, there were 410 (57.5%) reliable strains and 303 (42.5%) non-identified strains among the GPB identification results of 713 strains, using a microflex MALDI Biotyper (Bruker Daltonik GmbH, Bremen, Germany). The isolation appeared most often in the following order: Corynebacterium striatum, Bacillus cereus, Bacillus subtilis, Paenibacillus urinalis, and Listeria monocytogenes. Nearly three-fourths, 66 out of 89 (74.2%) of the strains for Corynebacterium striatum; 44 out of 60 (73.3%) strains for Bacillus cereus; and all (25 out of 25, 100%) Listeria monocytogenes strains were identified by their high scores of 2.0 or higher. Most (293 strains out of 303) non-identified strains were strains isolated only once and not significant as infectious bacilli. A total of 43 out of 50 (86.0%) strains matched and were able to be identified based on the 16 rRNA sequencing comparison results of strains that were isolated twice or more within the same patient and significant as infection bacilli. Non-matching among 5 out of 7 strains was not identified, even with MALDI-TOF MS. In conclusion, GPB can be identified in blood cultures using MALDI-TOF MS. This can be done accurately with ease, rapidly, and at a low cost. It is also thought to be helpful in GPB diagnosis and treatment.

• KSBB Journal
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• 제23권5호
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• pp.425-430
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• 2008

생체에서의 황화수소는 의약 분야와 발효 산업에 있어서 중요한 역할을 하고 있다. 본 연구에서는 Saccharomyces cerevisiae을 이용하여 기질인 L-cysteine과 $\beta$-mercaptoethanol로부터 $\beta$-replacement 반응에 인한 황화수소를 발생시킬 수 있는 효소를 간편하고 신속하게 동정하는 방법의 확립을 목적으로 하였다. 효소에 의해 발생된 황화수소와 Pb-acetate의 반응으로 생성된 Pb-S를 gel상에서 간편하게 확인한 후, 확인된 단백질들을 이온교환컬럼를 수행한 후 gel에서 추출하는 방법으로 MALDI-TOFMS의 시료를 간단히 얻을 수 있었다. PMF 방법과 MS/MS ion search 분석을 통해 간편하게 효모에서 황화수소를 형성할 가능성이 있는 세가지 단백질의 동정에 성공하였다. 이 세 가지 단백질은 CYS3, CYS4, MET17 유전자의 단백질로서 cystathionine $\gamma$-lyase, CBS, OASS 임이 밝혀졌다. 그리고 이 세 단백질들은 L-cysteine과 $\beta$-mercaptoethanol의 존재하에서 황화수소를 실제로 생성함을 확인하였다. 본 연구에서 표적의 물질을 생산하는 단백질들을 젤상에서의 활성측정과 MALDI-TOF MS를 이용하여 간단히 그리고 정확하게 동정하는 방법을 확립하였다.

• Bulletin of the Korean Chemical Society
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• 제35권5호
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• pp.1409-1412
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• 2014

Sex hormones are important metabolites in vertebrates' development and reproduction. For rapid screening sex hormones, matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) is one of the promising analytical platforms, but MALDI MS faces many challenges in detecting steroids such as low ionization efficiency and matrix background interference. One potential strategy to overcome matrix interference in the low m/z region is using a cyclodextrin (CD)-supported matrix for steroid analysis since CD-supported matrixes are known to effectively suppress matrix-related ion signals. In this study, we aimed to find the optimal CD-supported matrix for the analysis of the nonderivatized sex steroids. Our results showed that the ${\alpha}CD$-supported 2,5-dihydroxybenzoic acid (DHB) matrix efficiently ionized all three major classes of sex hormones, estrogens, androgens, and progestagens, with low or no matrix background and also with high sensitivity. In addition, the ${\alpha}CD$-supported DHB matrix mainly generated molecular ions or protonated ions of sex hormones, and this enabled us to obtain information-rich tandem mass spectra which potentially lead to unambiguous identification of steroid species from complex metabolite mixtures.

• Bulletin of the Korean Chemical Society
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• 제25권12호
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• pp.1791-1800
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• 2004

Angiotensin I, a model decapeptide, was glycosylated and partially hydrolyzed with HCl (6 N, 80 $^{\circ}C$, 4 h), aminopeptidase, and carboxypeptidase Y. A single peptide mass map obtained from truncated peptides in the partial acid hydrolysate of angiotensin and its glycosylation product mixture by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry enabled sequencing of angiotensin by a combinatorial procedure. MALDI-TOF and electrospray ionization (ESI) tandem mass spectrometric results indicate that both the N-terminal amino group of aspartic acid and the guanidinium group of the second residue arginine are glycosylated.

• Macromolecular Research
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• 제11권5호
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• pp.341-346
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• 2003

A poly(ethylene oxide)-b-poly(L-lactide) diblock copolymer (PEO-b-PLLA) is characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and a block length distribution map is constructed. Although the MALDI- TOF mass spectrum of PEO-b-PLLA is very complicated, most of the polymer species were identified by isolating the overlapped isotope patterns and by fitting the overlapped peaks to the Schulz-Zimm distribution function. Reconstructed MALDI-TOF MS spectrum was nearly identical to the measured spectrum and this method shows its potential to be developed as an easy and fast analysis method of low molecular weight block copolymers.

• Journal of Microbiology and Biotechnology
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• 제27권9호
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• pp.1593-1601
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• 2017

Vibrio species are generally recognized as pathogens predominant in seafood along coastal areas. The food industry has sought to develop efficient microbial detection methods. Owing to the limits of conventional methods, this study aimed to establish a rapid identification method for Vibrio isolated from Korea, based on matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Four different preparation procedures were compared to determine the appropriate means to pretreat Vibrio species, using 17 isolates and five reference strains. Extended direct transfer and full formic acid extraction methods using bacterial colonies on agar plates revealed very low identification rates. Formic acid and trifluoroacetic acid (TFA) extractions using bacterial broth cultures were also performed. All Vibrio isolates and reference strains prepared by TFA extraction were successfully identified to the species level (17/22, 77.3%) and to the genus level (5/22, 22.7%). Thus, TFA extraction was considered the most appropriate method to pretreat Vibrio species for MALDI-TOF MS. The remaining 33 isolates and two reference strains were prepared by TFA extraction and analyzed by MALDI-TOF MS. Overall, 50 isolates were identified to the species level (40/50, 80%) and to the genus level (10/50, 20%). All isolates were identified as 43 V. alginolyticus, six V. parahaemolyticus, and one V. vulnificus species. V. alginolyticus and V. parahaemolyticus were isolated from fish offal (87.5% and 12.5%, respectively), seawater (91.3%, 8.7%), and shellfish (62.5%, 37.5%), whereas V. alginolyticus and V. vulnificus were isolated from sediment (90.9% and 9.1%, respectively). This study established a reliable system of MALDI-TOF MS preparation and analysis for Vibrio identification.

• Bulletin of the Korean Chemical Society
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• 제28권12호
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• pp.2354-2358
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• 2007

MALDI-TOF-MS technique was applied to obtain structural and compositional information of synthetic polyamides, Nylon6 and Nylon66. Mass spectra of both the original and the hydrolyzed polyamide samples were analyzed using the self calibration method as well as the internal calibration method with the standard materials of known masses. The MALDI-TOF mass spectra of Nylon6 samples showed the presence of protonated, sodiated, and potassiated ions that were assigned to cyclic and NH2/COOH terminated linear oligomers. From the MALDI-TOF mass spectra of Nylon66 samples, the potassiated linear oligomers with three different end groups are identified as well as the cyclic oligomers, i.e., NH2/COOH terminated oligomers, NH2/NH2 terminated oligomers, and COOH/COOH terminated oligomers. Full characterization of the molecular species and end groups present in the polyamide samples has been achieved, and also the changes in mass spectral patterns after the hydrolysis of the samples are presented.

• Bulletin of the Korean Chemical Society
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• 제28권9호
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• pp.1499-1509
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• 2007

Proteomic analyses of synaptic vesicle fraction from rat brain have been performed for the better understanding of vesicle regulation and signal transmission. Two different approaches were applied to identify proteins in synaptic vesicle fraction. First, the isolated synaptic vesicle proteins were treated with trypsin, and the resulting peptides were analyzed using a high-pressure capillary reversed phase liquid chromatography/tandem mass spectrometry (cRPLC/MS/MS). Alternatively, proteins were separated by two-dimensional gel electrophoresis (2DE) and identified by matrix-assisted laser desorption ionization mass spectrometry (MALDI-TOF/MS). Total 18 and 52 proteins were identified from cRPLC/MS-MS and 2DE-MALDI-TOF-MS analysis, respectively. Among them only 2 proteins were identified by both methods. Of the proteins identified, 70% were soluble proteins and 30% were membrane proteins. They were categorized by their functions in vesicle trafficking and biogenesis, energy metabolism, signal transduction, transport and unknown functions. Among them, 27 proteins were not previously reported as synaptic proteins. The cellular functions of unknown proteins were estimated from the analysis of domain structure, expression profile and predicted interaction partners.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2004년도 춘계학술발표대회
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• pp.238-238
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• 2004

세포 내에서 발현되고 있는 protein들의 양상을 분석하기 위한 기법으로 최근 proteomics에 기초하여 2차 전기영동과 MALDI-TOF MS에 의한 protein 분석방법이 개발되었는데, 특정 조직에 또는 특정 발생시기에 특이적으로 발현되는 protein의 발현양과 발현양상을 비교ㆍ분석하는데 매우 효과적으로 이용될 수 있다. 최근 체세포 핵이 식기술을 이용하여 동물의 복제가 성공하고 있지만, 임신 중이나 분만시 유사산이 많이 나타나 전반적인 효율이 크게 낮아 실용화에 지장을 초래하고 있다. (중략)