The presence of phosphate in glycogen

Abstract

Despite the great amount of work carried out on glycogen structure there are severai aspects which remain obscure. Glycogen isolated by mild methods has a very high molecular weight and appears to have labile bonds of unknown nature [l] and some -S-Slinkages [2]. Furthermore, protein is believed to form part of the glycogen molecule [3 ] and to be involved in the initiation of its biosynthesis [4,5]. Although other polysaccharides are known to contain bound phosphate, namely starch [6], glycogen is believed to be free from it. In fact, the lower the phosphate the purer the glycogen was considered to be [7-9 J. This paper reports studies in which radioactive phosphate was administered to rats and moulds and then was found to follow glycogen during fractionation and degradation. The evidence is compatible with the presence of glycogen-bound phosphate.