A Re-examination of the Molecular Structure of Yeast Glucan

Although the presence of chains of #-(1 -*3)- linked D-glucose residues in yeast glucan is well established (Northcote, 1963), the nature and location of other glucosidic linkages is uncertain. On the basis of methylation analysis, Bell & Northcote (1950) suggested that the glucan was highly branched, had B-(1-*2)-interchain linkages, and an average chain length of about 9 glucose residues. However, since on partial acid hydrolysis yeast glucan gave rise to a mixture of oligosaccharides containing both B-(1-*3)-and -(1 -*6)-linkages, Peat, Whelan & Edwards (1958a) concluded that the glucan was a linear molecule containing certain sequences of ,B-(1 -*3)and ,-(1 -*6)-linked glucose residues. The presence of (1 -*6)-linkages in yeast