IN-VIVO CONVERSION OF 6-O-SULFO-L-GALACTOPYRANOSYL RESIDUES INTO 3,6-ANHYDRO-L-GALACTOPYRANOSYL RESIDUES IN GRACILARIA-CHILENSIS BIRD, MCLACHLAN ET OLIVEIRA

The agar polysaccharides of the red seaweed Gracilaria chilensis Bird, McLachlan et Oliveira were labelled with the stable isotope C-13 by p ulse feeding (NaHCO3)-C-13 to samples of this alga acclimatised to ind oor culture. C-13 NMR spectroscopy of the labelled polysaccharides ext racted from these samples has been used to demonstrate conversion in v ivo of 6-O-sulfo-L-galactopyranosyl residues into 3,6-anhydro-L-galact opyranosyl residues. The 6-O-sulfo-L-galactopyranosyl residues can be linked to either 6-O-methyl-D-galactopyranosyl residues or D-galactopy ranosyl residues. (C) 1996 Elsevier Science Ltd.