Structural studies on the oligomers from the polysaccharide of Gracilaria textori (Rhodophyta) using ß-agarase and 13C-NMR spectroscopy
Résumé
The 60% ethanolic extract from Gracilaria textorii (Rhodophyta) was degraded with .beta.-agarase, and certain charged (sulfated) and neutral oligosaccharides were separated by using DEAE Sephadex A 25 and Bio- gel P6, P2 chromatographic techniques. Some of the charged oligomers were verified to be neoagarotetraose- 63 - sulfate (DP2), neoagarohexaose- 63, 65 - disulfate (DP3) and neoagarooctaose - 63, 65, 67- trisulfate (DP4) by using 13C- and 1H - NMR spectroscopy. One neutral oligomer was assumed to be a mixture of methylated neoagarotetraoses (DP2) by 1H - NMR spectroscopy. These oligomers assigned by their chemical shifts may be used as the model compounds for the structural investigation of the agar - type sulfated polysaccharides using the .beta.- agarase degradation method.