Molecular Structure of Carbohydrates

Abstract

PROF. W. N. HAWOKTH'S presidential address to Section B (Chemistry) deals with the molecular structure of carbohydrates. Ten years have elapsed since the structural model of glucose was first presented as the six-atom ring form, an observation communicated to NATURE in 1925. This model now can be regarded as the unit of the carbohydrates cellulose, starch and glycogen. At the outset it was essential to investigate the mode of union of pairs of glucose units which occur in cellobiose and maltose, the bioses to which cellulose and starch give rise by graded breakdown processes. This occurs through the groups at the first carbon atom in one residue and the fourth carbon atom in a second residue, which furnish the oxygen bond uniting two glucose units in these bioses. The spatial disposition of this bond provides the reason for the different identities of starch and cellulose. In other carbohydrates the linking follows a different choice.