Discrimination of Neolacto-Series Gangliosides with α2−3- and α2−6-Linked N-Acetylneuraminic Acid by Nanoelectrospray Ionization Low-Energy Collision-Induced Dissociation Tandem Quadrupole TOF MS

• Published in: Analytical chemistry (Washington) Vol. 75; no. 21; pp. 5719 - 5725
• Main Authors: Meisen, Iris, Peter-Katalinić, Jasna, Müthing, Johannes
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.11.2003
• Subjects: Analytical chemistry; Analytical, structural and metabolic biochemistry; Biological and medical sciences; Carbohydrates; Chemistry; Chromatographic methods and physical methods associated with chromatography; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Miscellaneous; Other biological molecules; Other chromatographic methods; Spectrometric and optical methods; Collisional activation; Oligosaccharide; Granulocyte; Fragmentation pattern; Fatty acids; Ring cleavage; Electrospray; Quadrupole spectrometer; Immunological method; Low energy; Thin layer chromatography; Ganglioside; Time of flight method; Mass spectrometry MS/MS; Neuraminic acid; Negative ion
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac0347617

A combined strategy of thin-layer chromatography immunostaining and negative ion nanoelectrospray low-energy CID mass spectrometry was established for the differentiation of isomeric α2−3 and α2−6 sialylated neolacto-series monosialogangliosides from human granulocytes. The gangliosides investigated differed in the ceramide moiety by substitution with C16:0 or C24:1 fatty acid and in their oligosaccharide chains due to nLc4 and nLc6 core structures. With respect to the type of sialylation, the homogeneity of the HPLC-purified ganglioside fractions was verified by use of specific anti-Neu5Acα2−3Galβ1−4GlcNAc-R and anti-Neu5Acα2−6Galβ1−4GlcNAc-R antibodies. A clear-cut series of fragment ions for both types of isomeric gangliosides, carrying α2−3- and α2−6-linked neuraminic acid, respectively, was obtained by low-energy CID. Additionally, a characteristic ring cleavage was detected exclusively in all species with Neu5Acα2−6Galβ1−4GlcNAc terminus, regardless of ceramide fatty acid and oligosaccharide chain lengths. The diagnostic 0,2X4/6 ions, generated by ring cleavage of an α2−6-linked neuraminic acid are accompanied by a simultaneous decrease of the corresponding Y4/Y6 ions. These results suggest the unequivocal discrimination of individual α2−3- and α2−6-sialylated neolacto-series monosialogangliosides by distinct fragmentation patterns in low-energy CID tandem MS.