Liver glycogen fragility in the presence of hydrogen-bond breakers

• Published in: International journal of biological macromolecules 2024-05, Vol.268 (Pt 1), p.131741-131741, Article 131741
• Main Authors: Tan, Xinle, Wang, Ziyi, Cheung, Ut, Hu, Zhenxia, Liu, Qinghua, Wang, Liang, Sullivan, Mitchell A., Cozzolino, Daniel, Gilbert, Robert G.
• Format: Article
• Language: English
• Subjects: animal models; Animals; blood glucose; Diabetes; dimethyl sulfoxide; Dimethyl Sulfoxide - chemistry; glucose; Glycogen; Guanidine - chemistry; Guanidine - pharmacology; guanidines; homeostasis; hydrogen; Hydrogen Bonding; Hydrogen-bond breaker; liver; Liver - metabolism; Liver Glycogen - metabolism; Male; Mice; Molecular structure; Mouse model; polymers; urea; Urea - chemistry
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2024.131741

Glycogen, a complex branched glucose polymer, is responsible for sugar storage in blood glucose homeostasis. It comprises small β particles bound together into composite α particles. In diabetic livers, α particles are fragile, breaking apart into smaller particles in dimethyl sulfoxide, DMSO; they are however stable in glycogen from healthy animals. We postulate that the bond between β particles in α particles involves hydrogen bonding. Liver-glycogen fragility in normal and db/db mice (an animal model for diabetes) is compared using various hydrogen-bond breakers (DMSO, guanidine and urea) at different temperatures. The results showed different degrees of α-particle disruption. Disrupted glycogen showed changes in the mid-infra-red spectrum that are related to hydrogen bonds. While glycogen α-particles are only fragile under harsh, non-physiological conditions, these results nevertheless imply that the bonding between β particles in α particles is different in diabetic livers compared to healthy, and is probably associated with hydrogen bonding. [Display omitted] •Glycogen is found as small β particles bound together as agglomerate α particles.•These agglomerates fragment into smaller particles in dimethyl sulfoxide.•The fragilities of diabetic and non-diabetic mouse-liver glycogens are different.•Fragile particles had IR spectral changes on treatment with H-bond disruptors•Fragility was only under extreme conditions but indicates a structural difference.