Identification of the sialosyl-sialosyl linkage in biosynthesized gangliosides

Herbert C. Yohe, Robert K. Yu

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Abstract

A technique was developed to examine the sialosyl-sialosyl linkage in the minute quantities of complex gangliosides biosynthesized in vitro. The disialoganglioside, GD31 1 The ganglioside nomenclature used here is that described by Svennerholm. The gangliosides are designated as follows: GM3: II3NeuAc-LacCer; GM1: II3NeuAc-GgOse4Cer; GD3: II3(NeuAc)2LacCer; GD1a: IV3NeuAc, II3NeuAc-GgOse4Cer; and GT1a: IV3(NeuAc)2, II3NeuAc-GgOse4Cer., and the trisialoganglioside, GT1a, were biosynthesized as secondary products by the reaction of CMP-(4-14C)sialic acid with the glycolipid substrates, lactosyl ceramide and GM1 ganglioside, respectively. Following periodate oxidation-borohydride reduction, the intact sialic acid residue, and the susceptible sialic acid residue converted into an N-acetylheptulosaminic acid residue, were released by hydrolysis, esterified, separated, and analyzed for radioactivity. Analysis of the biosynthesized GD3 and GT1a gangliosides indicated radioactivity in both the susceptible and the nonsusceptible sialic acid residues, demonstrating that a sialosyl-(2→8)-sialosyl linkage had been synthesized. When the primary products (GM3 and GD1a, respectively) of the synthesis just described were examined, radioactivity was detected, as expected, only in the susceptible sialic acid residue. Because the N-acetylneuraminic acid and N-acetylheptulosaminic acid derivatives formed in the reaction were identified by chromatography, the standards used for comparison were verified by g.l.c.-m.s.

Original languageEnglish (US)
Pages (from-to)1-9
Number of pages9
JournalCarbohydrate Research
Volume93
Issue number1
DOIs
StatePublished - Jun 16 1981
Externally publishedYes

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ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Organic Chemistry

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