title: Analysis of behavior of sodiated sugar hemiacetals under low-energy collision-induced dissociation conditions and application to investigating mutarotation and mechanism of a glycosidase.
abstract: 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.
authors.affiliation: Mitsubishi Kagaku Institute of Life Sciences (MITILS), Machida-shi, Tokyo, Japan. kokanee@mitils.jp
authors.forename: Osamu
authors.initials: O
authors.lastname: Kanie
authors.forename: Ayako
authors.initials: A
authors.lastname: Kurimoto
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Kanie
authors.forename: Shusaku
authors.initials: S
authors.lastname: Daikoku
authors.forename: Atsuko
authors.initials: A
authors.lastname: Ohtake
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Suzuki
mesh_terms: D055162:Biocatalysis; D002236:Carbohydrate Conformation; D002241:Carbohydrates / Q000737:chemistry*; D005740:Gases; D006868:Hydrolysis; D010694:Lactase-Phlorizin Hydrolase / Q000378:metabolism*; D007785:Lactose / Q000737:chemistry; D013058:Mass Spectrometry; D012399:Rotation; D012964:Sodium / Q000737:chemistry*; D013237:Stereoisomerism; D013816:Thermodynamics
chemical_list: D002241:Carbohydrates; D005740:Gases; D012964:Sodium; D010694:Lactase-Phlorizin Hydrolase; D007785:Lactose