Journal of the Mass Spectrometry Society of Japan
Online ISSN : 1880-4225
Print ISSN : 1340-8097
ISSN-L : 1340-8097
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Volume 55, Issue 1
Displaying 1-9 of 9 articles from this issue
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REGULAR PAPERS
  • Characterization of Isomeric Unsulfated Glycosaminoglycan Oligosaccharides by Mass Spectrometry/Mass Spectrometry
    Toshikazu MINAMISAWA, Kiyoshi SUZUKI, Hiroshi MAEDA, Satoshi SHIMOKATA ...
    2007 Volume 55 Issue 1 Pages 1-6
    Published: 2007
    Released on J-STAGE: February 15, 2007
    DOIhttps://doi.org/10.5702/massspec.55.1
    JOURNAL FREE ACCESS
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    Both saturated and unsaturated forms of isomeric unsulfated glycosaminoglycan (GAG) oligosaccharides, i.e., tetrasaccharides of chondroitin (CH) and hyaluronan (HA), were analyzed by electrospray ionization mass spectrometry/mass spectrometry. Although the only structural difference between them was the hydroxyl group at the C-4 position in N-acetylhexosamine (GalNAc or GlcNAc, respectively), given the same m/z value of precursor ions, these isomers in both their saturated and unsaturated forms could be separated by careful examination of diagnostic fragment ions in their product ion mass spectra when the relative abundances of these fragment ions were considered. In addition, the product ion mass spectrum of the unsaturated HA tetrasaccharide was compared with its linkage isomer, N-acetylheparosan tetrasaccharide. In this case, the isomers were more easily differentiated by comparing their characteristic spectral patterns. By adopting this approach, systematic differentiation of isomeric unsulfated GAG oligosaccharides should be achieved by means of fragmentation. It should also contribute widely to GAG-related biochemical and medicinal research in the future.
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  • Mass Spectrometric Elucidation of Phenolic Oxidation Processes with Cu2+-Adduct
    Akio HAYASHI, Noriko TANIGUCHI, Kazuo TSUJIMOTO, Isao KUBO
    2007 Volume 55 Issue 1 Pages 7-13
    Published: 2007
    Released on J-STAGE: February 15, 2007
    DOIhttps://doi.org/10.5702/massspec.55.7
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    Formation of ε complex with 2-hydroxy-6-[8′(Z),11′(Z),14′-pentadecatrienyl]benzoic acid (anacardic acid) and copper ion in the respective ratios of 2 : 1 and 1 : 1 at room temperature was observed by electrospray ionization mass spectrometry. The oxidation of 3-(3,4-dihydroxyphenyl)alanine (DOPA) in the presence of anacardic acid showed competitive inhibition with temporary reduction from dopaquinone to DOPA. In the oxidation of neurotensin, the oxidized products, dopaquinone-derivatives, were observed. Mass spectrometry revealed that the enzymatic oxidation of tyrosine residue is inhibited by anacardic acid.
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  • Simulation of Beam Profile of Multi-Turn Time-of-Flight Mass Spectrometers
    Michisato TOYODA, Masaru NISHIGUCHI
    2007 Volume 55 Issue 1 Pages 17-24
    Published: 2007
    Released on J-STAGE: February 15, 2007
    DOIhttps://doi.org/10.5702/massspec.55.17
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    The ion beam profiles of the multi-turn time-of-flight mass spectrometers “MULTUM” and “MULTUM II” were simulated using the ion trajectory simulation program “TRIO 2.0.” These ion optical systems satisfy the “perfect focusing” conditions and are suitable for an imaging mass spectrometer in stigmatic mode. From the simulation, it was clear that the higher order aberration of MULTUM II is smaller than that of MULTUM. A smaller initial lateral angular deviation makes aberration after circulation smaller in both the ion optical systems. In the ion optical system MULTUM II, the ion images should be measured at even numbered cycles, because the second-order coefficient (x¦xx) will be cancelled after every two cycles.
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  • Direct Analysis of Cultured Cells with Matrix-Assisted Laser Desorption/Ionization on Conductive Transparent Film
    Yuki SUGIURA, Shuichi SHIMMA, Yasunobu MORIYAMA, Mitsutoshi SETOU
    2007 Volume 55 Issue 1 Pages 25-31
    Published: 2007
    Released on J-STAGE: February 15, 2007
    DOIhttps://doi.org/10.5702/massspec.55.25
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    Direct tissue analysis and ion imaging using mass spectrometry extract significant information directly from complex biological samples. In this paper, we introduce a method for the direct analysis of cultured cells. To analyze cultured cells by direct mass spectrometry (MS), we incubated HEK293T cells directly on an indium-tin-oxide layer on polyethylene terephthalate film. After fixation of cells on the film, matrix application was performed by spray-droplet method, which is a two-step matrix application method to improve the ionization efficiency of biological tissue samples. By direct MS of HEK293T cells, we obtained mass spectra of approximately 350 protein signals with good quality. Furthermore, we profiled proteins as digested products and identified major signals by applying an on-tissue digestion direct MS/MS method, which is the procedure for enzymatic protein digestion of biological tissue samples. This new approach enables proteomic analysis directly from the cell culture system.
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COMMENTARIES
  • Time-of-Flight Secondary Ion Mass Spectrometry Imaging of Biodevices
    Satoka AOYAGI
    2007 Volume 55 Issue 1 Pages 33-38
    Published: 2007
    Released on J-STAGE: February 15, 2007
    DOIhttps://doi.org/10.5702/massspec.55.33
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    Time-of-flight secondary ion mass spectrometry (TOF-SIMS) imaging provides ten-nanometer-scale chemical images of biodevices. It is one of the most sensitive surface analysis methods and has recently been applied in life sciences. TOF-SIMS is useful for the evaluation of biodevice surfaces, because it provides ten-nanometer-scale mapping and chemical structures of immobilized proteins on devices. In addition, TOF-SIMS requires no pretreatment of samples, such as labeling with a fluorescent probe or coating with metallic thin films. In this paper, the principles of TOF-SIMS and data analysis methods are introduced, and some examples of biodevice observation with TOF-SIMS are described.
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  • Imaging Mass Spectrometry
    Yasuhide NAITO
    2007 Volume 55 Issue 1 Pages 39
    Published: 2007
    Released on J-STAGE: February 15, 2007
    DOIhttps://doi.org/10.5702/massspec.55.39
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Letters to the Editor
Letter from the Editor-in-Chief
  • Comments on Abscissa Labeling of Mass Spectra
    Ken-ichi YOSHINO
    2007 Volume 55 Issue 1 Pages 51-62
    Published: 2007
    Released on J-STAGE: February 15, 2007
    DOIhttps://doi.org/10.5702/massspec.55.51
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    Mass spectrometers separate ions according to each mass/charge value, which is not a dimensionless quantity. However, the m/z value indicated in the abscissa of mass spectra is defined as a dimensionless quantity and not a numerical value the same as the mass/charge value in kilograms/coulombs (kg/C). The numerical value of m/z converted from the mass/charge value depends on the unified atomic mass unit, u (or dalton, Da) and the physical constant “elementary charge,” e that is also the atomic unit of charge. This conversion confuses many mass spectrometrists with regard to the abscissa labeling of mass spectra. To avoid this confusion, a new unit, “thomson” (unit symbol, Th), was proposed, and defined as 1 Th=1 u/atomic charge=1 Da/atomic charge. However, this unit is not yet well known and has been deprecated.
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