• 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.

• Mass Spectrometry Letters
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• v.6 no.3
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• pp.80-84
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• 2015

Here, we demonstrate the use of MALDI-TOF as a fast and simple analytical approach to evaluate the DNA-binding capability of various peptides. Specifically, by varying the amino acid sequence of the peptides consisting of lysine (K) and tryptophan (W), we identified peptides with strong DNA-binding capabilities using MALDI-TOF. Mass spectrometric analysis reveals an interesting novel finding that lysine residues show sequence selective preference, which used to be considered as mediator of electrostatic interactions with DNA phosphate backbones. Moreover, tryptophan residues show higher affinity to DNA than lysine residues. Since there are numerous possible combinations to make peptide oligomers, it is valuable to introduce a simple and reliable analytical approach in order to quickly identify DNA-binding peptides.

• Bulletin of the Korean Chemical Society
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• v.20 no.11
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• pp.1299-1302
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• 1999

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was used to demonstrate cross-linking of peptides induced by transglutaminase. The presence of ε-( Υ-glutamyl)lysine isopeptide cross-link in the acid hydrolysate of the cross-linking reaction mixture was also demonstrated by MALDI-TOF-MS without prior separation. MALDI-TOF-MS quickly provided peptide mass maps after pronase digestion of the cross-linked peptide adduct, which enabled us to monitor the hydrolytic sequence. Pronase appears to preferentially hydrolyze peptide bonds distant from the cross-link before hydrolyzing peptide bonds around the cross-link. The results suggest that pronase digestion followed by MALDI-TOF-MS could be used for determination of amino acid sequence around a modification site.

• Bulletin of the Korean Chemical Society
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• v.26 no.5
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• pp.763-768
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• 2005

An improved tandem time-of-flight (TOF) mass spectrometer for the photodissociation (PD) study of ions generated by matrix-assisted laser desorption ionization (MALDI), MALDI-TOF-PD-TOF, has been designed and constructed. Recording a full spectrum with better than unit mass resolution even in low mass range has been achieved without reflectron voltage stepping which was needed in the previous version. Other aspects of the improvement, such as those in the data system which now allow 10-100 times faster spectral acquisition than with the previous instrument, are described. Rationale for the ideas which have led to the improvements is presented also.

• Journal of Microbiology and Biotechnology
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• v.29 no.6
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• pp.887-896
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• 2019

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS)-based pathogen identification relies on the ribosomal protein spectra provided in the proprietary database. Although these mass spectra can discern various pathogens at species level, the spectra-based method still has limitations in identifying closely-related microbial species. In this study, to overcome the limits of the current MALDI-TOF MS identification method using ribosomal protein spectra, we applied MALDI-TOF MS of low-mass profiling to the identification of two genetically related Bacillus species, the food-borne pathogen Bacillus cereus, and the insect pathogen Bacillus thuringiensis. The mass spectra of small molecules from 17 type strains of two bacilli were compared to the morphological, biochemical, and genetic identification methods of pathogens. The specific mass peaks in the low-mass range (m/z 500-3,000) successfully identified various closely-related strains belonging to these two reference species. The intensity profiles of the MALDI-TOF mass spectra clearly revealed the differences between the two genetically-related species at strain level. We suggest that small molecules with low molecular weight, 714.2 and 906.5 m/z can be potential mass biomarkers used for reliable identification of B. cereus and B. thuringiensis.

• 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.

• Mass Spectrometry Letters
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• v.4 no.2
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• pp.38-40
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• 2013

Glycans released from ovalbumin by PNGase F were analyzed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry using three different dihydroxybenzoic acid (DHB) matrix systems: 2,5-DHB, 2,6-DHB, and a 2,5-DHB/2,6-DHB binary matrix. Relative to the results obtained with the single-component matrices (2,5-DHB or 2,6-DHB), the 2,5-DHB/2,6-DHB binary matrix boasted lower background noise and higher sensitivity. A total of 16 glycan peaks were observed using the 2,5-DHB/2,6-DHB binary matrix, while only 10 and 9 glycan peaks were observed using the 2,5-DHB and 2,6-DHB matrices, respectively.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.477-482
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• 2011

The structural analysis of polytrimethylene terephthalate (PTT) and characterization of the hydrolytic degradation products after acid hydrolysis were performed using MALDI-TOF mass spectrometry. Mass spectra of the PTT samples were analyzed using a self-calibration method as well as an internal calibration method with standard materials of known masses. PTT structures constituting the samples were determined from the analyses of the spectra, and their relative compositions were estimated. The MALDI-TOF mass spectra of the acid-hydrolyzed PTT sample showed three main series of oligomer products with different end groups in accordance with the hydrolysis schemes. From the spectra of both $Na^+$ and $K^+$ adducts, it was concluded that the PTT samples have higher affinity for $Na^+$ compared with $K^+$ and therefore show higher ionization efficiency with sodium ions when dithranol is used as a matrix. Two different wavelength laser beams ($\lambda$ = 337 nm and 355 nm) were tested and it was observed that the 355 nm beam was more efficient in obtaining the MALDI spectra of PTT using dithranol as a matrix under our experimental conditions.

• Journal of Photoscience
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• v.8 no.2
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• pp.83-86
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• 2001

Structural analyses of oligosaccharide-malononitrile derivatives were conducted by matrix-assisted laser desorption/ionization post-source decay (MALDI-PSD) analysis in positive ion mode. The malononitrile derivatives of oligosaccharides, which were developed for highly sensitive detection of multi-component oligosaccharides by negative ion electrospray ionization mass spectrometry (ESI MS), were detected by positive-ion MALDI with the detection limit of 2 pmol level from the crude derivatization sample. The used matrix affected drastically the analytical results of oligosaccharide-malononitrile derivative by matrix-assisted laser desoprtion/ionization mass spectrometry (MALDI MS). The malononitrile derivatization of oligosaccharide also affect the patterns of MALDI-PSD spectra and give much more structural information than the free oligosaccharide.

• Applied Chemistry for Engineering
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• v.28 no.3
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• pp.263-271
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• 2017

The application of mass spectrometry to polymer science has rapidly increased since the development of MALDI-TOF MS. This review summarizes current polymer analysis methods using MALDI-TOF MS, which has been extensively applied to analyze the average molecular weight of biopolymers and synthetic polymers. Polymer sequences have also been analyzed to reveal the structures and composition of monomers. In addition, the analysis of unknown end-groups and the determination of polymer concentrations are very important applications. Hyphenated techniques using MALDI-tandem MS have been used for the analysis of fragmentation patterns and end-groups, and also the combination of SEC and MALDI-TOF MS techniques is recommended for the analysis of complex polymers. Moreover, MALDI-TOF MS has been utilized for the observation of polymer degradation. Ion mobility MS, TOF-SIMS, and MALDI-TOF-imaging are also emerging technologies for polymer characterization because of their ability to automatically fractionate and localize polymer samples. The determination of polymer characteristics and their relation to the material properties is one of the most important demands for polymer scientists; the development of software and instrument for higher molecular mass range (> 100 kD) will increase the applications of MALDI-TOF MS for polymer scientists.