The molecular structure and shape of yeast glycogen

Abstract

Samples of yeast glycogen were prepared by various methods. A comparison of the products failed to give any evidence for the existence of more than one glycogen in yeast. An explanation is put forward to account for the insolubility of part of the yeast glycogen when the cell is cytolysed by NaOH soln. Yeast glycogen was shown to be composed of glucose molecules linked for the most part by 1: [alpha]: 4 links in unit chains of approx. 12 glucose radicals. The hydrolysis limits obtained by the action of beta-amylase indicated some slight difference in the position of the branching point in yeast glycogen and in rabbit-liver glycogen. No anomalous links hydrolysable by Z enzyme or emulsin were found in yeast glycogen. The viscosity measurements indicate an asymmetric shape for the yeast glycogen molecule compared with that of rabbit-liver glycogen. An axial ratio indicating this asymmetry was calculated.