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Recent advances in mass spectrometry make our view of glycosphingolipids (GSLs) com- pletely different from the previous one. LC-MS is applicable to GSL mixture in a smallamount, and provides structural information of carbohydrate chains and ceramides andpossibly quantitative results. However, several subjects remain to be carefully clarified.Critical subjects are matrices used for enhancing ionization of GSLs and the prepara- tion of standard or isotope-labeled GSLs for quantitation. We have tested several matrices for neutral GSLs and acidic GSLs (gangliosides) in the analysis of negative ion mode. Negative ion mode provides more fragment ions derived from carbohydrate chains and ceramides. Matrices used for LC analysis with a C30 reversed phase column of neutral GSLs, such as ammonium formate, formic acid, ammonium acetate, and acetic acid, give adduct ions and the ratios of molecularions [M - H]- and adduct ions are different among molecular species of GlcCer as the simplest neutral GSL. Ammonium bicarbonate containing solvents give lesser amount of adducts and can be used for comparing changes of molecular species of neutral GSLs produced by the different conditions of cultured cells or comparing neutral GSLs of different subsets of cells isolated from living organisms. In the analysis of gangliosides, we detected GM1(NeuAc) as a single charged ion [M – H]-,and GM1(NeuGc) as a double charged ion [M - 2H]-2. Other ganglisoides such as GD1, GT1, and GQ1 molecules were detected as double charged ions, therefore, GM1(NeuAc) gives the highest m/z values among these gangliosides, thus detection effi- ciency becomes very low. We have successfully applied LC-MS analysis to gangliosides of mouse thymocytes and CD4+ and CD8+ T cells (Nagafuku et al. 2012). Fortunately, these gangliosides contain N-glycolylneuraminic acid and give double charged ions, even in the case of GM1. When they are activated, the down regulation of CMP- NeuAc hydroxylase which is the rate liming step for the expression of NeuGc containing ganglisodies (Naito et al. 2007), is possibly triggered. Then, the sensitive detection of GM1(NeuAc) must be assured. This is also required for the analysis of microdomains of neuronal cell mem-brane of neural degenerative diseases such as Alzheimer disease and Parkinson disease.

저자

• Akemi Suzuki [ Institute of Glycoscience, Tokai University, Hiratsuka ]
• Hideshi Fujiwaki [ Shimadzu Co, Kyoto, Japan ]
• Yoshikatsu Umemura [ Shimadzu Co, Kyoto, Japan ]

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간행물

표지보기 관심저널 등록

• 간행물명

  한국당과학회 학술대회

• 간기

  연간

• 수록기간

  2006~2022

• 십진분류

  KDC 517 DDC 614