Abstract:

The properties of high molecular weight glycogen extracted from rat liver and of that prepared in vitro with muscle phosphorylase and liver branching enzyme have been compared. The stability at different pH values was measured spectrophotometrically for liver, corn, and synthetic glycogen. The former is more labile, but the shape of the pH-stability curve is very similar for all of them. Borate, copper, and iron accelerate the decomposition of the three types of glycogen. Sonication produces breakdown but affects in the same way synthetic and liver glycogen. After shortening the outer chains with β-amylase, native liver glycogen becomes slightly more stable to acid treatment and decomposes giving smaller molecules than the untreated glycogen. Glycogen extracted from livers of toad and pigeon was similar in molecular weight distribution and acid lability to that of rat liver. Rat muscle glycogen had a molecular weight of about 8 million. © 1967.