Gangliosides GM2, GM1 and GD1b were radiolabelled at C-6 of the terminal galactose or N-acetylgalactosamine by the galactose oxidase/[3H]NaBH4 method; gangliosides GM2, GM1, Fuc-GM1 and GD1a were radiolabelled at C-3 of the long chain base by the 2,3-dichloro-5,6-dicyanobenzoquinone/[3H]NaBH4 method. By application of an original HPLC procedure, eight different molecular species were prepared from each labelled ganglioside. Each of these species was characterized by the presence of one of the following long chain bases:erythro C18 sphingosine, threo C18 sphingosine, erythro C18 sphinganine, threo C18 sphinganine, erythro C20 sphingosine, threo C20 sphingosine, erythro C20 sphinganine and threo C20 sphinganine. From GD1b only the species containing the erythro forms of long chain bases were obtained. The individual molecular species were more than 99% homogeneous and had a radiopurity better than 99%. The molecular species of the same ganglioside, radiolabelled at C-3 of the long chain base, had identical specific radioactivity, namely 1.17, 1.25, 0.85 and 1.28 Ci/mmol for GM2, GM1, Fuc-GM1 and GD1a respectively. The molecular species of the same ganglioside, radiolabelled at C-6 of terminal galactose or N-acetylgalactosamine, had similar specific radioactivity, namely 1.34-1.40, 1.44-1.51, 1.37-1.44 Ci/mmol for GM2, GM1 and GD1b respectively.
- ganglioside long chain bases
- ganglioside radioactive labelling
- HPLC separation
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