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2,4-Dinitrophenylhydrazides of polysialogangliosides
T Tanaka1, K Miyazaki, Y Kishimoto
1Kennedy Institute, Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205.
Chemistry and Physics of Lipids
|October 1, 1988
Summary
Gangliosides can be converted to dinitrophenylhydrazides for HPLC analysis. This study reveals that derivatization of GT1b ganglioside can yield two products due to variable sialic acid carboxyl group modification.
Area of Science:
- Biochemistry
- Analytical Chemistry
- Glycobiology
Background:
- Gangliosides are complex glycosphingolipids crucial for neuronal function.
- HPLC methods are vital for ganglioside analysis.
- Previous methods for ganglioside derivatization have limitations.
Purpose of the Study:
- To characterize the products of ganglioside derivatization using 2,4-dinitrophenylhydrazine HCl and dicyclohexylcarbodiimide.
- To understand the structural variations in derivatized gangliosides, particularly GT1b.
- To investigate the extent of derivatization in various polysialogangliosides.
Main Methods:
- Ganglioside derivatization using 2,4-dinitrophenylhydrazine HCl and dicyclohexylcarbodiimide.
- Analysis of derivatized products using plasma desorption mass spectrometry (PDMS).
- Characterization using proton magnetic resonance (1H NMR) and other chemical/physical techniques.
Main Results:
- Derivatization of GT1b ganglioside resulted in two distinct products, indicating modification of one or two sialic acid carboxyl groups.
- Underivatized carboxyl groups formed lactones with hydroxyl groups.
- GD1a showed full derivatization, while GD1b, GT1a, and GQ1b exhibited partial derivatization, likely due to steric hindrance in polysialogangliosides.
Conclusions:
- The derivatization method yields structurally heterogeneous products, impacting quantitative analysis.
- Steric hindrance influences the extent of sialic acid carboxyl group derivatization in polysialogangliosides.
- Further characterization is needed to refine HPLC methods for accurate ganglioside determination.