Analysis of behavior of sodiated sugar hemiacetals under low-energy collision-induced dissociation conditions and application to investigating mutarotation and mechanism of a glycosidase

Proc Jpn Acad Ser B Phys Biol Sci. 2009;85(6):204-15. doi: 10.2183/pjab.85.204.


Analysis of anomericity is one of the most important issues in the structure elucidation of carbohydrates. Mass spectrometry (MS)-based methods are of particular interest and important to address the issue related to resolving anomericity of monosaccharide units in a glycan. However, direct analysis of hemiacetals has not been possible by MS because of the nonavailability of information regarding the gas-phase behavior of such ion species. We addressed this issue by using stage-discriminated energy-resolved mass spectrometry (ERMS) at the stages of MS(n) and MS(n+1) and showed that such analysis can be made. This was achieved by proving that individual anomers can be identified and that the equilibrium of sodium adducted ion species of alpha- and beta-anomers can be negated in the gas phase under collision-induced dissociation (CID) conditions. On the basis of these results, we could 1) observe the mutarotation of lactose and 2) speculate the hydrolysis mechanism of endo-glycosylceramidase by using mass spectrometry.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biocatalysis
  • Carbohydrate Conformation
  • Carbohydrates / chemistry*
  • Gases
  • Hydrolysis
  • Lactase-Phlorizin Hydrolase / metabolism*
  • Lactose / chemistry
  • Mass Spectrometry
  • Rotation*
  • Sodium / chemistry*
  • Stereoisomerism
  • Thermodynamics


  • Carbohydrates
  • Gases
  • Sodium
  • Lactase-Phlorizin Hydrolase
  • Lactose