Biochemical properties of N-methylamides of sialic acids in gangliosides.
A simple and rapid method for the preparation of N-methylamides ( - CONHCH3) of sialic acids in gangliosides and biochemical properties of the modified gangliosides are described. The sialic acid carboxyl groups of gangliosides were esterified with CH3I-dimethylsulfoxide, followed by heating with monomethylamine. The modified gangliosides were chemically identified by TLC, IR spectroscopy, GLC-mass spectrometry and NMR spectroscopy. The N-methylamide derivative of GM1 produced a high titer IgG antibody. The antibody weakly cross-reacted with the methylester of GM1 and its reductive derivative but did not react with the intact GM1. A monoclonal antibody (M2590) specific for GM3 did not react with carboxyl-modified GM3 (methylester, N-methylamide, and reduced GM3), but it reacted with modified GM3 which contains the C7-analog of the sialic acid. Clostridium perfringens and Arthrobacter ureafaciens sialidases did not hydrolyze the N-methylamide derivatives, methylesters or reductive derivatives of the gangliosides and, furthermore, these derivatives did not inhibit the actions of these sialidases.
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Nakamura
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Handa
D000577:Amides / Q000032:analysis*; D000818:Animals; D000918:Antibody Specificity; D002417:Cattle; D002855:Chromatography, Thin Layer; D004285:Dogs; D004797:Enzyme-Linked Immunosorbent Assay; D005732:Gangliosides / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry; D006736:Horses; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007120:Immunochemistry; D009682:Magnetic Resonance Spectroscopy; D010084:Oxidation-Reduction; D012794:Sialic Acids / Q000032:analysis*; D013055:Spectrophotometry, Infrared; D013194:Staining and Labeling
D000577:Amides; D005732:Gangliosides; D012794:Sialic Acids