• 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.

• BMB Reports
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• v.53 no.7
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• pp.349-356
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• 2020

Mass spectrometry (MS) is an ideal tool for analyzing multiple types of (bio)molecular information simultaneously in complex biological systems. In addition, MS provides structural information on targets, and can easily discriminate between true analytes and background. Therefore, imaging mass spectrometry (IMS) enables not only visualization of tissues to give positional information on targets but also allows for molecular analysis of targets by affording the molecular weights. Matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) MS is particularly effective and is generally used for IMS. However, the requirement for an organic matrix raises several limitations that get in the way of accurate and reliable images and hampers imaging of small molecules such as drugs and their metabolites. To overcome these problems, various organic matrix-free LDI IMS systems have been developed, mostly utilizing nanostructured surfaces and inorganic nanoparticles as an alternative to the organic matrix. This minireview highlights and focuses on the progress in organic matrix-free LDI IMS and briefly discusses the use of other IMS techniques such as desorption electrospray ionization, laser ablation electrospray ionization, and secondary ion mass spectrometry.

• Bulletin of the Korean Chemical Society
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• v.25 no.12
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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.

• Journal of Microbiology and Biotechnology
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• v.17 no.2
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• pp.207-217
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• 2007

The Saccharomyces0 cerevisiae KNU5377 strain, which was isolated from spoilage in nature, has the ability to convert biomass to alcohol at high temperatures and it can resist against various stresses [18, 19]. In order to understand the defense mechanisms of the KNU5377 strain under menadione (MD) as oxidative stress, we used several techniques for study: peptide mass fingerprinting (PMF) by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry (MS) followed by two-dimensional (2D) gel electrophoresis, liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS), and surface-enhanced laser desorption ionization-time of flight (SELDI-TOF) technology. Among the 35 proteins identified by MALDI-TOF MS, 19 proteins including Sod1p, Sod2p, Tsa1p, and Ahp1p were induced under stress condition, while 16 proteins were augmented under normal condition. In particular, five proteins, Sod1p, Sod2p, Ahp1p, Rib3p, Yaf9p, and Mnt1p, were induced in only stressed cells. By LC-ESI-MS/MS analysis, 37 proteins were identified in normal cells and 49 proteins were confirmed in the stressed cells. Among the identified proteins, 32 proteins were found in both cells. Five proteins including Yel047cp and Met6p were only upregulated in the normal cells, whereas 17 proteins including Abp1P and Sam1p were elevated in the stressed cells. It was interesting that highly hypothetical proteins such as Ynl281wp, Ygr279cp, Ypl273wp, Ykl133cp, and Ykr074wp were only expressed in the stressed cells. SELDI-TOF analysis using the SAX2 and WCX2 chips showed that highly multiple-specific protein patterns were reproducibly detected in ranges from 2.9 to 27.0 kDa both under normal and stress conditions. Therefore, induction of antioxidant proteins, hypothetical proteins, and low molecular weight proteins were revealed by different proteomic techniques. These results suggest that comparative analyses using proteomics might contribute to elucidate the defense mechanisms of KNU5377 under MD stress.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.3 no.2
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• pp.54-58
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• 2017

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF MS) is one of the powerful methods that enable analysis of small molecules as well as large molecules up to about 500,000 Da without severe fragmentation. MALDI-TOF MS, thus, has been a very useful an analytical tool for the confirmation of synthetic molecules, probing PTMs, and identifying structures of a given protein. In recent nuclear medicine, MALDI-TOF MS liner ion mode helps researcher calculate the average number of chelator(or linkage) per an antibody conjugate, such as DOTA-(or DFO-) trastuzumab for labeling a medical radioisotope. This simple technique can be utilized to improve the labeling method and control the quality at the development of antibody-based radiopharmaceuticals, which is very effected to diagnosis and therapy for in vivo tumor cells, with radioisotopes like $^{89}Zr$, $^{64}Cu$, and 177Lu. To minimize the error, MALDI-TOF MS measurement is repeatedly performed for each sample in this study, and external calibration is carried out after data collection.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.2
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• pp.134-143
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• 2005

Collagen is the important structural proteins in mammals with various peptide composition and cross-linkings. The direct analysis of collagen protein was not suitable because of its structural complexity and diversity. In this study, we suggest the simple way of collagen analysis by introducing matrix-assisted laser desorption/ionization time-of flight mass spectrometry (MALDI-TOF MS) to identify the collagen and its trypsin-digested fragments, and by subsequent time-of-flight tandem mass spectrometry(Q-TOF MS/MS) to analyze the amino acid sequences of identified fragments. Using the collagen samples extracted from the tail of mouse, 10 separated bands were found in SDS-PAGE, and the masses of most bands could be more finely determined by MALDI-TOF MS. When each 10 separated proteins was tryptic digested and introduced to MALDI-TOF, the Gly1056-Arg1073 fragment from $\alpha_1$-chain was identified in four bands, and the Gly1056-Arg1073 fragment from $\alpha_2$-chain was identified in five bands, both in type I collagen. Although few fragments were found because of the cross-linkings left in digested collagen sample, it could be determined that the type I collagen existed at least in 7 separated bands. When the amino acid sequences of two identified fragments were analyzed by Q-TOF MS/MS, both sequences were identical with those determined by MALDI-TOF MS. It suggested that the two peaks in MALDI-TOF MS caused by the fragments identified in this work could be used as the fingerprint to simply identify type I collagen in protein samples.

• Biomedical Science Letters
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• v.23 no.4
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• pp.395-401
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• 2017

Various preclinical and clinical trials have been conducted the efficacy of celastrol. In data presented in the current manuscript is the first trial to inhibit Helicobacter pylori with celastrol. In this study, the quantitative change of various H. pylori proteins including CagA and VacA by the anti-bacterial effect of celastrol was determined. The anti-H. pylori effects of celastrol was investigated by performing 2-dimensional electrophoresis and additional supporting experiments. After 2-dimensional electrophoresis analysis, spot intensities were analyzed and then each spot was identified using matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS) or peptide sequencing using Finnigan LCQ ion trap mass spectrometer (LC-MS/MS). The results show that celastrol has multiple effects on protein expression in H. pylori.

• 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.

• Journal of Microbiology and Biotechnology
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• v.16 no.12
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• pp.1990-1994
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• 2006

Fusarium proliferatum KGL0401 was previously isolated from Physalis alkekengi var. francheti plant roots and exhibited a high GA productivity. A gas chromatography-mass spectrometry (GC-MS) analysis of extracts of the culture fluid of F proliferatum KGL0401 also revealed the presence of $GA_1$, $GA_3$, $GA_4$, $GA_7$, $GA_{20}$, and $GA_{24}$. Therefore, the present study conducted a proteome analysis of waito-c rice treated with the culture fluid of the isolated F proliferatum KGL0401 to identify the protein expression triggered by the GA-containing culture fluid. The results revealed the overexpression of 180 protein spots in the sample treated with the culture fluid. Among them, 75 induced proteins were selected and analyzed by MALDI-TOF (matrix-assisted laser desorption-iorrization time-of-flight) mass spectrometry, followed by database searching, and 51 proteins were identified.

• Journal of Dairy Science and Biotechnology
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• v.30 no.2
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• pp.131-137
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• 2012

Rapid and reliable identification of microorganisms is a key for tracing the relationship between the target bacteria and related infectious diseases. Various identification methods such as classical phenotypic analysis, numerical taxonomic analysis, and DNA sequencing have been widely used to classify microorganisms in milk and dairy products. Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) identifies targeted bacteria in milk and milk products. Several studies have demonstrated that MALDI-TOF MS identification is an efficient and inexpensive method for the rapid and routine identification of isolated bacteria. MALDI-TOF MS could provide accurate identification of bacteria in milk and milk products at the serotype or strain level and enable antibiotic resistance profiling within minutes.