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

Abstract

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 β-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)-β-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 β-D-configuration.

Ispitivana je struktura homopolisaharida izolovanog iz suvog aktivnog pekarskog kvasca (Saccharomyces cerevisiae), metodom metilovanja perjodatnom oksidacijom, masenom spektrometrijom, NMR spektroskopijom i enzimskom hidrolizom, kao novim pristupom u izučavanju strukture polisaharida. Dobijeni rezultati ukazuju da polisaharid, koji se sastoji iz D-glukoze, ima (1→3)-D-glukopolimerni niz kao osnovni, a da su D-glukopiranozni ostaci vezani za osnovni niz preko položaja O-6 i to ili kao pojedinačne bočne jedinice ili kao deo oligomernih bočnih grupa koje čine (1→3)-D-glukopiranozil ostaci. Konfiguracija glikozidnih veza je β-D-tipa.