The fine structure of Purkinje fiber glycogen. A comparative study of negatively stained and cytochemically stained particles

Abstract

The fine structure of Purkinje fiber glycogen isolated and negatively stained and PA-TSC-SP stained in sections was revealed by high resolution electron microscopy and analyzed with an optical diffractometer. Irrespective of the preparative procedure, the glycogen seemed to be composed of subunits of the same order of magnitude (diameter approximately 3 nm) which were arranged in a regular pattern. These observations are discussed in relation to the preparative techniques used and are compared with models of glycogen proposed on the basis of chemical data. A gap still seems to exist between the ultrastructural and chemical data. However, the fine structure revealed for Purkinje fiber glycogen treated in two different ways suggests that the glycogen molecules partly contain a regular arrangement of the intramolecular chains.