A glucan from active dry baker s yeast (Saccharomyces cerevisiae): A chemical and enzymatic investigation of the structure

The structure of a polysaccharide consisting of D-glucose isolated from the cell-wall of active dry baker s yeast (Saccharomyces cerevisiae) was investigated by using methylation analysis, periodate oxidation, mass spectrometry, NMR spectroscopy, and enzymic hydrolysis, as a new approach in determination of structures. The main structural feature of the polysaccharide deduced on the basis of the obtained results is a linear chain of (1->3)-linked b-D-glucopyranoses, a part of which is substituted through the positions O-6. The side units or groups are either a single D-glucopyranose or (1->3)-b-oligoglucosides, linked to the main chaing through (1->6)-glucosidic linkages. The low optical rotation as well as the 13C-NMR and FTIR spectra suggest that the glycosidic linkages are in the b-D-configuration.