Molecular structure of glycogen in diabetic liver

摘要

Liver glycogen (involved in maintaining blood-sugar levels) is a hyperbranched glucose polymer containing beta particles (diameter 20 nm), which can form composite alpha particles (diameter 50-300 nm), and includes a small but significant amount of bound protein. Size distributions of glycogen from livers of healthy and diabetic mice were examined using size-exclusion chromatography with two separate eluents: aqueous eluent and dimethylsulfoxide (DMSO) eluent. Morphologies were examined with transmission electron microscopy. Diabetic glycogen (DG) exhibited many alpha particles in the mild water-based solvent, but in DMSO, which breaks H bonds, these degraded to beta particles; alpha particles however were always present in healthy glycogen (HG). This DG fragility shows the binding of beta into alpha particles is different in HG and DG. The diabetic alpha particle fragility may be involved with the uncontrolled blood-sugar release symptomatic of diabetes: small beta particles degrade more easily to glucose than alpha particles. This has implications for diabetes management.