Analysis of monosaccharides, fatty constituents and rare O-acetylated sialic acids from gonads of the starfish Asterias rubens

• Published in: Biochimie 2006-02, Vol.88 (2), p.171-178
• Main Authors: Zanetta, Jean-Pierre, Srinivasan, Vinayaga, Schauer, Roland
• Format: Article
• Language: English
• Subjects: Animals; Asterias; Asterias - anatomy & histology; Asterias - chemistry; Asterias rubens; Asteroidea; Fatty Acids - analysis; Gonads - chemistry; Marine; Molecular Structure; Monosaccharides - analysis; N-acetylneuraminic acid; N-glycolyl-8-methyl-neuraminic acid; N-glycolylneuraminic acid; N-linked glycans; O-acetylated sialic acids; Sialic Acids - analysis; Unsaturated lipids
• ISSN: 0300-9084; 1638-6183
• DOI: 10.1016/j.biochi.2005.07.010

A previous study (Bergwerff et al., Biochimie 74 (1992) 25–37) reported that sialic acids present in Asterias rubens gonads were essentially composed of 8-methyl- N-glycolylneuraminic acid (Neu5Gc8Me), a large part of it being acetylated in position 9. Using GC/MS of heptafluorobutyrate derivatives (Zanetta et al., Glycobiology 11 (2001) 663–676) on the chloroform/methanol soluble and insoluble fractions, we showed that most sialic acids were found in the latter and demonstrated that all sialic acids were derived from N-glycolylneuraminic acid, most of them being 8-methylated, but that the majority were also acetylated in position 4 or 7 (or both positions). GC/MS analyses of the constituents liberated using acid-catalysed methanolysis verified that major glycoprotein-bound glycans were N-linked and of the gluco-oligomannosidic type. Major fatty acids were poly-unsaturated (especially C20:4) and long-chain bases were C22:1 phytosphingosine and C22:2 6-hydroxysphingenine. Major monosaccharides found in the chloroform/methanol extract (quinovose and fucose) were derived from steroidal saponins.