title: Optimal conditions to radiolabel (3H or 14C) aminosugar-containing glycosphingolipids by de-N-acetylation and re-N-acetylation.
abstract: The optimal conditions were examined for selective re-N-acetylation with 14C or 3H.acetic anhydride of de-N-acetylated aminosugar-containing glycosphingolipids. Re-N-acetylation, which is nearly quantitative within 10 minutes in methanol, occurs selectively up to a maximal 100% yield when using a molar ratio of 5 mol of acetic anhydride per mole of aminosugar present in the glycosphingolipid. Above this molar ratio, it was observed some O-acetylation of carbohydrates which could be removed by mild alkali treatment. The method allows the choice of 14C- or 3H-labeling of glycosphingolipids with a final specific radioactivity which depends solely on the one of acetic anhydride. The binding of specific antibodies to glycosphingolipids, which was abolished upon de-N-acetylation, was again detectable after re-N-acetylation with radioactive acetic anhydride, suggesting that the native structures were recovered. This procedure of radiolabeling offers safety, rapidity and broad applicability to alkali-stable aminosugar-containing glycosphingolipids.
authors.affiliation: INSERM U.218, Centre Léon Bérard, Lyon, France.
authors.forename: A
authors.initials: A
authors.lastname: Rebbaa
authors.forename: J
authors.initials: J
authors.lastname: Portoukalian
mesh_terms: D000107:Acetylation; D000818:Animals; D001923:Brain Chemistry; D002250:Carbon Radioisotopes; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D004912:Erythrocytes / Q000737:chemistry; D005677:G(M1) Ganglioside / Q000737:chemistry; D005679:G(M3) Ganglioside / Q000737:chemistry; D005732:Gangliosides; D006028:Glycosphingolipids / Q000737:chemistry*; D006801:Humans; D007553:Isotope Labeling / Q000379:methods*; D008545:Melanoma / Q000737:chemistry; D014316:Tritium
chemical_list: D002250:Carbon Radioisotopes; D005679:G(M3) Ganglioside; D005732:Gangliosides; D006028:Glycosphingolipids; D014316:Tritium; C038244:ganglio-N-triaosylceramide; D005677:G(M1) Ganglioside; C018835:asialo GM1 ganglioside