FAB CID-MS/MS of In-Source Fragment Ions as a Means to Differentiate Linkage Isomers of Branched Oligosaccharides: Lea and Lex Type Glycoconjugates

Yoko OHASHI; Tadashi II; Masayuki KUBOTA; Shigeki NUNOMURA; Haruki NIWA; Mamoru OHASHI; Tomoya OGAWA; Yoshitaka NAGAI

doi:10.5702/massspec.46.45

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FAB CID-MS/MS of In-Source Fragment Ions as a Means to Differentiate Linkage Isomers of Branched Oligosaccharides: Le^a and Le^x Type Glycoconjugates

Yoko OHASHI, Tadashi II, Masayuki KUBOTA, Shigeki NUNOMURA, Haruki NIWA, Mamoru OHASHI, Tomoya OGAWA, Yoshitaka NAGAI

Author information

Yoko OHASHI
Glycobiology Research, Frontier Research Program, The Institute of Physical and Chemical Research
Tadashi II
Glycobiology Research, Frontier Research Program, The Institute of Physical and Chemical Research
Masayuki KUBOTA
Glycobiology Research, Frontier Research Program, The Institute of Physical and Chemical Research
Department of Applied Physics and Chemistry, The University of Electro-Communications
Shigeki NUNOMURA
Tokyo Pharmaceutical Research Laboratories, Nissin Food Products Co., Ltd.
Haruki NIWA
Department of Applied Physics and Chemistry, The University of Electro-Communications
Mamoru OHASHI
Department of Applied Physics and Chemistry, The University of Electro-Communications
Tomoya OGAWA
Laboratory of Synthetic Cellular Chemistry, The Institute of Physical and Chemical Research
Faculty of Agriculture, University of Tokyo
Yoshitaka NAGAI
Glycobiology Research, Frontier Research Program, The Institute of Physical and Chemical Research
Mitsubishikasei Institute of Life Sciences

Keywords: Lewis-type trisaccharide propyl glycosides, Linkage isomers, Glycoconjugates, In-source fragment ion, Selection of the precursor ion, Differentiation between Le^a- and Le^x-, Linkage-specific product ions, Electronegativity, Hydrogen bonding, Aromatization

JOURNAL FREE ACCESS

1998 Volume 46 Issue 1 Pages 45-52

DOI https://doi.org/10.5702/massspec.46.45

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Abstract

Here we report that FAB CID-MS/MS, choosing an ion originating from the in-source degradation prior to the full acceleration of the molecule-related ion as the precursor, is an excellent means to differentiate linkage isomers. FAB CID-MS/MS performed in this way results in a product ion spectrum, which is enriched with the fragmentation information, and which may thus indicate the position of the newly formed OH group already produced in the ion source. Linkage knowledge may be classified into one of three categories as described later. This method was applied to acidic Lewis-type glycoconjugates —putative ligands for selectins [L. L. W. Cooling, D.-S. Zhang, and T. A. W. Koerner, Trends in Glycosci. Glycotech., 9, 191 (1997)]— and their neutral analogs to differentiate linkage isomers by mass spectrometry. With these glycoconjugates FAB CID-MS/MS having [M+H]⁺s as the precursor ions is a good means to distinguish the linkage isomers only in simple cases, but not in general cases. By using ions originating from in-source degradation prior to the full acceleration of the molecule-related ion as the precursor, we were able to differentiate between Le^a and Le^x.

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