R. Falshaw et Rh. Furneaux, CARRAGEENAN FROM THE TETRASPORIC STAGE OF GIGARTINA-DECIPIENS (GIGARTINACEAE, RHODOPHYTA), Carbohydrate research, 252, 1994, pp. 171-182
The structure of the polysaccharide isolated from tetrasporophytic pla
nts of the New Zealand red alga Gigartina decipiens has been determine
d by chemical and spectroscopic techniques. It is a linear polymer com
posed primarily of alternating 3-linked beta-D-galactopyranosyl 2-sulp
hate and 4-linked alpha-D-galactopyranosyl 2,6-disulphate residues. Ab
out 15% of the 3-linked residues have an additional sulphate ester gro
up at the 6-position. Aside from this small extra sulphate substitutio
n, the structure is that of the idealised lambda-carrageenan. Good qua
lity solution-state C-13 NMR spectra were recorded and interpreted for
this carrageenan and for the carrageenans produced from it by solvoly
tic desulphation and alkali modification.