Enzyme treatment of glycogen particles in rat liver and muscle

Abstract

Liver and striated muscle glycogen particles, both isolated and in tissue sections, were examined in the electron microscope. They were treated enzymatically with diastase, amylase, and pepsin. Pepsin was used because it is believed that glycogen in tissues is bound to proteins. The enzymatic treatment of ultrathin sections gave the following results: (a) Liver glycogen particles disappeared from the sections after digestion with any one of the enzymes used; (b) muscle glycogen particles did not disappear from the sections even after a double treatment with pepsin and diastase. Glycogen particles isolated from either liver or striated muscle were digested by diastase. Pieces of liver and muscle, incubated in 0.1% glucose to synthesize more glycogen, contained glycogen particles which appeared larger than usual, as seen in the electron microscope. Following diastase treatment, these particles returned to their original dimensions in muscle sections, and disappeared completely from the liver sections.