Gangliosides of the starfish Aphelasterias japonica, evidence for a new linkage between two N-glycolylneuraminic acid residues through the hydroxy group of the glycolic acid residue

Isolation and Structure of Hematoside-Type Ganglioside from the Starfish Linckia laevigata

“…The stereochemistry of the ceramide moiety is presumed to be (2S,3S,4R,2ЈR), since the aforementioned 13 C-NMR signals assignable to C-1, 2, 3, 4 and 2Ј of 1 are in good agreement with those of the synthetic phytosphingosine-type…”

“…When the signals due to the sugar moieties of 1 and 3 (ceramide b-lactoside) in their 13 C-NMR spectra were compared, they were nearly identical except for the signals ascribable to NeuGc and C-3 of Gal ( Table 1). The downfield signal for C-3 (d 77.7) of the Gal unit resulting from glycosylation 7,8) in the 13 C-NMR spectrum of 1 indicates that the NeuGc residue is located at C-3 of the Gal unit.…”

“…In its 13 C-NMR spectrum ( Fig. 1, Table 1), 1 exhibits the characteristic signals of a phytosphingosine-type ceramide, 5) possessing a 2-hydroxy fatty acid and a sugar moiety at C-1 [d: 70.5 (C-1), 51.4 (C-2), 75.7 (C-3), 72.5 (C-4), 175.9 (C-1Ј) and 72.5 (C-2Ј)].…”

“…1, Table 1), 1 exhibits the characteristic signals of a phytosphingosine-type ceramide, 5) possessing a 2-hydroxy fatty acid and a sugar moiety at C-1 [d: 70.5 (C-1), 51.4 (C-2), 75.7 (C-3), 72.5 (C-4), 175.9 (C-1Ј) and 72.5 (C-2Ј)]. The 13 C-NMR spectrum of 1 also features signals due to three anomeric carbons at d: 105.5, 104.5 and 100.8, one of which (d: 100.8) is a quaternary carbon signal, indicating the presence of a sialic acid residue. Therefore, 1 is suggested to be a phytosphingosine-type ganglioside, possessing 2-hydroxy fatty acid groups and three monosaccharide units.…”

“…Therefore, 1 is suggested to be a phytosphingosine-type ganglioside, possessing 2-hydroxy fatty acid groups and three monosaccharide units. It is further presumed to have normaltype fatty acids and normal-and iso-type long-chain bases, since the carbon signals for the terminal methyl groups are observed at d 14.1 (normal form) and 22.8 (iso form) 6) in the 13 C-NMR spectrum ( Fig. 1, Table 1).…”