Derivatization for stabilizing sialic acids in MALDI-MS.

Sadanori Sekiya; Yoshinao Wada; Koichi Tanaka

doi:10.1021/ac050287o

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Derivatization for stabilizing sialic acids in MALDI-MS.

Sadanori Sekiya·Yoshinao Wada·Koichi Tanaka

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Abstract

While matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is useful in oligosaccharide analysis, the sialic acid, or N-acetylneuraminic acid (NANA), moiety of an oligosaccharide is liable to dissociation in- or postsource during mass measurement. In this study, we tried to stabilize the moiety by amidation, as in the case of peptides (Sekiya, S.; Wada, Y. Tanaka, K. Anal. Chem. 2004, 76, 5894-5902), and found 4-(4,6-dimethoxy-1,3,5-triazin-2yl)-4-methylmorpholinium chloride to be a desirable condensing agent. Amidation stabilized the glycosidic bond with NANA and suppressed its preferential cleavage by in-source decay, postsource decay, or collision-induced dissociation. In addition, the suppressed dissociation considerably improved the yield of the B/Y type ions for structural analysis by MS/MS. These results demonstrate that amidation is an effective derivatization to reinforce the structural analysis of sialylated oligosaccharides by MALDI-MS. In addition, amidation with (15)N-labeled ammonium chloride decreases the mass shift from the acid to amide form to just 0.013, reducing the complexity of mass spectral interpretation and database searching.

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Amination Carbohydrate Sequence Chromatography, High Pressure Liquid Humans Oligosaccharides Polysaccharides Sialic Acids Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization Transferrin Journal Article

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Sadanori Sekiya, Yoshinao Wada, Koichi Tanaka. 2005-08-01. Derivatization for stabilizing sialic acids in MALDI-MS.. https://doi.org/10.1021/ac050287o

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