title: Molecular insights into glycogen α-particle formation.
abstract: Glycogen, a hyperbranched complex glucose polymer, is an intracellular glucose store that provides energy for cellular functions, with liver glycogen involved in blood-glucose regulation. Liver glycogen comprises complex α particles made up of smaller β particles. The recent discovery that these α particles are smaller and fewer in diabetic, compared with healthy, mice highlights the need to elucidate the nature of α-particle formation; this paper tests various possibilities for binding within α particles. Acid hydrolysis effects, examined using dynamic light scattering and size exclusion chromatography, showed that the binding is not simple α-(1→4) or α-(1→6) glycosidic linkages. There was no significant change in α particle size after the addition of various reagents, which disrupt disulfide, protein, and hydrogen bonds and hydrophobic interactions. The results are consistent with proteinaceous binding between β particles in α particles, with the inability of protease to break apart particles being attributed to steric hindrance.
authors.affiliation: Centre for Nutrition & Food Sciences (Building 83/S434), Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, Qld 4072, Australia.
authors.forename: Mitchell A
authors.initials: MA
authors.lastname: Sullivan
authors.forename: Mitchell J
authors.initials: MJ
authors.lastname: O'Connor
authors.forename: Felipe
authors.initials: F
authors.lastname: Umana
authors.forename: Eugeni
authors.initials: E
authors.lastname: Roura
authors.forename: Kevin
authors.initials: K
authors.lastname: Jack
authors.forename: David I
authors.initials: DI
authors.lastname: Stapleton
authors.forename: Robert G
authors.initials: RG
authors.lastname: Gilbert
mesh_terms: D000818:Animals; D003920:Diabetes Mellitus; D004220:Disulfides / Q000378:metabolism; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D008112:Liver Glycogen / Q000737:chemistry* / Q000378:metabolism; D051379:Mice; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism*; D013552:Swine
chemical_list: D004220:Disulfides; D008112:Liver Glycogen; D011506:Proteins