The Molecular Size Distribution of Glycogen and its Relevance to Diabetes

Abstract

Glycogen is a highly branched polymer of glucose, functioning as a blood-glucose buffer. It comprises relatively small b-particles, which may be joined as larger aggregate a-particles. The size distributions from size-exclusion chromatography (SEC, also known as GPC) of liver glycogen from non-diabetic and diabetic mice show that diabetic mice have impaired a-particle formation, shedding new light on diabetes. SEC data also suggest the type of bonding holding b-particles together in a-particles. SEC characterisation of liver glycogen at various time points in a day/night cycle indicates that liver glycogen is initially synthesised as b-particles, and then joined by an unknown process to form a-particles. These a-particles are more resistant to degradation, presumably because of their lower surface area-to-volume ratio. These findings have important implications for new drug targets for diabetes management.

Starch and Glycogen Analyses: Methods and Techniques

“…Two often-used techniques are size exclusion chromatography, as mentioned previously [95,97,117,118,[202][203][204][205][206][207][208][209][210][211][212][213][214] and field flow fractionation, which allow the separation of small oligoglucans up to polyglucans [94,206,[215][216][217]. The advantage of the latter is the lack of potential glucan-matrix interactions that can result in unclean separation and false correlation [218,219].…”

Theoretical and experimental approaches to understand the biosynthesis of starch granules in a physiological context

“…The typical size of β-type glycogen particles in muscles ranges between 20 and 30 nm in diameter with a molecular mass of 10 6 -10 7 g/mol (Gilbert and Sullivan 2014). Assuming a spherical shape, particles would range from 4.2 × 10 3 to 1.4 × 10 4 nm 3 , containing between 6.2 × 10 3 and 6.2 × 10 4 glucose monomers (based on the molecular mass of 162 g/ mol monomers, which considers the loss of a water molecule during the formation of the glucosidic bond).…”

Brain Glycogen Structure and Its Associated Proteins: Past, Present and Future

“…Drochmans and colleagues were the first to describe the various levels of glycogen structure in native glycogen isolated from liver and muscle, and their observations were corroborated by others (Drochmans 1962;Revel 1964;Wanson and Drochmans 1968;Ryu et al 2009). The largest glycogen particle, named the α particle, is a rosette-shaped association of several smaller units, known as β particles, that can reach up to 300 nm in diameter and over 10 8 Daltons in molecular weight (Gilbert and Sullivan 2014;Prats et al 2018). Glycogen β particles typically range in size from 10-44 nm and have a molecular weight of 10 6 -10 7 Daltons (Shearer and Graham 2002;Sullivan et al 2012).…”