Ian J. Miller
The structure of polysaccharides from selected New Zealand species of Grateloupia
The structure of the polysaccharides extracted from New Zealand samples of Grateloupia was examined by 13C NMR spectroscopy and by chemical means, and was found to consist of alternating 3-linked and 4-linked residues. All Grateloupia polysaccharides had low levels of 2-O-methyl-3,6-anhydro-L-galactose, and variable levels of 6-O-methyl-D-galactose. The major diads of Grateloupia urvilleana polysaccharide were non-sulfated 3-linked galactose with 4-linked D-galactose-2-sulfate, and 3-linked galactose-2-sulfate with non-sulfated 3,6-anhydro-D-galactose. In Grateloupia stipitata and Grateloupia prolifera polysaccharides, approximately half the 4-linked units were in the L-form, and the diad comprising 3-linked D-galactose-2-sulfate and 4-linked L-galactose-2,3-disulfate, an entity previously found mainly in Champia species, was also present. The diads with 4-linked galactose in the D-form comprised 4-linked D-galactose or 3,6-anhydro-D-galactose, and these diads had the sulfation found in Grateloupia urvilleana, except that a large proportion of these diads had no sulfation at all. Although these polysaccharides contain the same sugars as Pachymenia polysaccharides, apart possibly from the diad comprising 3-linked galactose-2-sulfate and 3,6-anhydro-L-galactose, which is a minor component of the Grateloupia polysaccharides, the polysaccharides from the two genera have no diads in common.
Botanica Marina, Walter de Gruyter
Print ISSN: 0006-8055
Volume: 48, 04/2005
Pages: 157 - 166
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