• Macromolecular Research
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• v.11 no.5
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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.

• Mass Spectrometry Letters
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• v.13 no.4
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• pp.106-114
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• 2022

A rapid and reliable approach to the identification of microorganisms is a critical requirement for large-scale culturomics analysis. MALDI-TOF MS is a suitable technique that can be a better alternative to conventional biochemical and gene sequencing methods as it is economical both in terms of cost and labor. In this review, the applications of MALDI-TOF MS for the comprehensive identification of microorganisms and bacterial strain typing for culturomics-based approaches for various environmental studies including bioremediation, plant sciences, agriculture and food microbiology have been widely explored. However, the restriction of this technique is attributed to insufficient coverage of the mass spectral database. To improve the applications of this technique for the identification of novel isolates, the spectral database should be updated with the peptide mass fingerprint (PMF) of type strains with not only microbes with clinical relevance but also from various environmental sources. Further, the development of enhanced sample processing methods and new algorithms for automation and de-replication of isolates will increase its application in microbial ecology studies.

• Journal of Life Science
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• v.15 no.3 s.70
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• pp.427-433
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• 2005

With the completely discovery of the Drosophila genome sequence, the next great challenge is to extract its biological information by systematic expression and to perform functional analysis of the gene. Here we reported a proteome analysis of D. melanogaster with two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption ionization time-of-flight mass spectrometer (MALDI-TOF-MS). The cell extracts of D. melanogaster, $200{\mu}g$ were resolved to more than 400 silver-stained spots by 2-DE. The most abundant protein spots were ranged from 4.0-7.5 of pI and from 15-90 kDa of molecular weight. The excised spots were destained and in-gel digested by trypsin. The masses of the resulting peptide mixtures were measured by MALDI-TOF-MS. Identified proteins were compared with measured peptide mass and a dynamic peptide searching database which is accessible via the internet. The results revealed that identified proteins were produced by 59 genes derived from 65 protein spots.

• Biomedical Science Letters
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• v.24 no.2
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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.

• Environmental Mutagens and Carcinogens
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• v.26 no.1
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• pp.25-29
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• 2006

Antimicrobial peptides (AMPs) play an important role in this response by rapidly killing invading microorganisms. In this study antimicrobial peptide has been isolated from acidified whole body extract of a bivalve mollusk, the marine mussel (Mytilus coruscus). This peptide purified to homogeneity by gel-filtration and reversed-phase high performance liquid chromatography. The molecular weight was 1464.92 Da, determined by MALDI-TOF Mass spectrometry. In addition to growth inhibition of Escherichia coli D31.

• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1183-1186
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• 2011

The unique Br signature was utilized for C-terminal amino acid sequencing of model peptides. C-terminal carboxyl group was selectively derivatized in peptides, containing side chain carboxyl group, using 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride (EDC) and Br was introduced using 4-bromophenylhydrazine hydrochloride (BPH) in a one pot reaction. Matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) tandem mass spectra were obtained carrying the Br signature in the y-series ions. The Br signature facilitated C-terminal sequencing and discrimination of C-terminal carboxyl groups in the free acid and amide forms.

• Mass Spectrometry Letters
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• v.4 no.1
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• pp.21-23
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• 2013

The effects of trifluoroacetic acid (TFA) were evaluated on the generation of multiply charged ions of cytochrome c in a 2-nitrophloroglucinol (2-NPG) matrix in high-vacuum, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The presence of 1% TFA in the 2-NPG matrix solution was more effective in generating multiply charged protein ions than matrix solutions containing 0.1% or 0% TFA. Regarding the matrix itself, with 1% TFA, 2-NPG was significantly more effective in generating multiply charged ions than 2,5-dihydroxybenzoic acid (2,5-DHB). The maximum charge state of cytochrome c was +8 when using a 2-NPG matrix containing 1% TFA.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.406.3-407
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• 2002

Analysis of interferon alpha (IFN) modified with high molecular weight branched PEG was performed by capillary electrophoresis (CE) and MALDI-TOF mass spectrometry (MALDI-TOF MS). IFN was modified by the reaction of amine residues with an active ester of monomethoxy polyethylene glycol at various molar ratios. As a CE method. capilary electrophoresis sodium dodecyl sulfate nongel sieving (CE-SDS NGS) was performed using an uncoated capilary filled with a hydrophilic replaceable polymer network matrix. (omitted)

• Bulletin of the Korean Chemical Society
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• v.35 no.10
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• pp.3047-3051
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• 2014

In this paper, we describe a new method for the selective extraction and quantification of glutathione (GSH) using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and maleimide-presenting gold nanoparticles (Mal-AuNPs). Our strategy utilizes the Michael addition to selectively extract GSH, from chosen samples, onto the maleimide of Mal-AuNPs. After the extraction step, the GSH bound to the AuNPs was analyzed by MALDI-TOF MS in the presence of an internal standard which was prepared by reacting Mal-AuNPs with isotope-labeled GSH ($GSH^*$). The $GSH^*$ has the same structure as GSH but a higher molecular weight, and therefore, enables absolute quantification of GSH by comparing the mass signal intensities of the GSH- and $GSH^*$-conjugated alkanethiols. Our strategy was verified by analyzing GSH-spiked fetal bovine serum and NIH 3T3 cells.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.25 no.3
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• pp.1-21
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• 1999

화장품, 의료용, 가정용품 및 공업용제품에까지 광범위한 용도로 사용량이 많은 중요한 비이온 계면활성제의 종류 중에서 polyoxyethylene(POE) 부가형 계면활성제의 경우 그 부가몰수에 따라 특성이 달라지고 용도가 다르게 사용된다. 이때 부가된 분자들의 분자량이 크고 분포를 이루는 혼합물이기 때문에 분석이 매우 어렵다. 따라서 MALDI-TOF/MS 방법을 이용하여 이들의 분자량과 그 분포를 측정함으로써 쉽고 빠르게 측정할 수 있는 새로운 방법을 개발하고자 하였다. 이 논문에서는 화장품에 주로 사용되는 비이온 계면활성제를 선택하여 MALDI-TOF/AfS를 측정하여 스펙트럼으로부터 분자량 분포와 POE부가정도를 측정할 수 있었다. 그리고 이 조건을 적용하여 시중에 판매되는 제품에서 추출된 비이온 계면활성제의 MALDI-TOF/MS 스펙트럼으로부터 분자량 분포와 POE 부가 정도를 확인 할 수 있었다.