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Volume 57 (2009)
- Issue 6 Pages 371-
- Issue 5 Pages 331-
- Issue 4 Pages 241-
- Issue 3 Pages 117-
- Issue 2 Pages 45-
- Issue 1 Pages 1-
Volume 57, Issue 6
Displaying 1-4 of 4 articles from this issue
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REGULAR PAPER
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Tomoya KINUMI, Issey OSAKA, Akio HAYASHI, Takaaki KAWAI, Hiroyuki MATS ...2009 Volume 57 Issue 6 Pages 371-377
Published: December 01, 2009
Released on J-STAGE: December 15, 2009
JOURNAL FREE ACCESSOxidation of proteins leads to carbonylation—the formation of aldehydes or ketones-at the amino acid side chain and/or the terminal amino groups. Carbonylated proteins have been conventionally detected by UV absorption spectrometry of the stable adduct with 2,4-dinitrophenylhydrazine (DNPH). However, this routine method is limited to detection of the total carbonyl content and does not provide structural information. We developed an isotope-dilution method for the specific detection of carbonylated proteins using 12C6-DNPH and 13C6-DNPH. This method has the following steps: the oxidized protein or peptide is divided into two parts, and these parts are independently labeled with 12C6-DNPH and 13C6-DNPH; the mixtures of these two labeled solutions are subsequently measured with matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The carbonylated peptide was found by searching for a doublet peak having a mass difference of 6 Da. We examined oxidized angiotensin I and oxidized lysozyme prepared by treatment with NaOCl. The oxidized angiotensin I showed four pairs of doublet peaks in the MALDI-TOF mass spectrum. The structure was determined by tandem mass spectrometry. In the case of tryptic digest of the oxidized lysozyme, two carbonylated products could be easily identified even in a complex mixture. The use of 13C6-DNPH provides rapid and accurate detection of carbonylated peptides even in complex mixtures.View full abstractDownload PDF (306K)
COMMENTARIES
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Ken-ichi YOSHINO2009 Volume 57 Issue 6 Pages 379-385
Published: December 01, 2009
Released on J-STAGE: December 15, 2009
JOURNAL FREE ACCESSThis is a mass spectrometry glossary recording of daily used “unofficial terms” which are not recorded in the official glossary. In addition, the misuse examples which ignore the definition of scientific terminology and the terms which become the obsolete words officially are recorded.View full abstractDownload PDF (535K) -
—Superexcited States of Molecules—Noriyuki KOUCHI2009 Volume 57 Issue 6 Pages 387-391
Published: December 01, 2009
Released on J-STAGE: December 15, 2009
JOURNAL FREE ACCESSSuperexcited states of molecules are defined as neutral excited states that have energies higher than the first ionization energy. They are much different from ordinary excited states of which energies are below the first ionization energy. The characteristics and dynamics of the superexcited states are discussed to substantiate that the molecule obtaining energy higher than the first ionization energy does not always ionize.View full abstractDownload PDF (450K)
REVIEW
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—Basic Understanding of Penning Ionization—Masatoshi UKAI2009 Volume 57 Issue 6 Pages 393-404
Published: December 01, 2009
Released on J-STAGE: December 15, 2009
JOURNAL FREE ACCESSPenning ionization, one of the fundamental chemical reactions involved in ionized gases, is recently demonstrated to facilitate a new type soft ionization source with a high-efficiency in mass spectrometry. In this review I present indispensable physico-chemical understanding of Penning ionization to design and to operate Penning ionization ion source.View full abstractDownload PDF (1699K)
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