Glycogen is a biological polysaccharide nanoparticle, complex carbohydrate, branched polymer of glucose, found in humans in muscles and liver, in bacteria and yeasts, discovered in 1857 by Claude Bernard who called it 'la matière glycogène'. Many studies have focused on the metabolism of glycogen, some of which were awarded a Nobel Prize (1947 Carl and Gerty Cori. 1970 Louis Leloir. 1971 Earl Sutherland. 1992 Edmond Fischer and Edwin Krebs). 

It is made up of molecules so small that they cannot be detected with light microscopy, but with an electron microscope. Its function is the storage of glucose and carbon to be released in times of need (1) and represents an immediate form of energy available to tissues that need it. 

Biodegradable, non-toxic, it is found in Streptomyces coelicolor, Escherichia coli, Streptomyces albidoflavus, Aliger gigas.

Industrially it is in the form of an odourless white powder obtained by processing the liver of animals (rabbits, cattle), oysters, Mytilus edulis or maize starch with 30% sodium hydroxide and precipitated with ethanol. Soluble in water and hot ethanol, insoluble in ethanol and ether.

What it is used for and where

Medical

Biomedical applications in the form of biodegradable fibres and gels, as drug delivery carriers, immunomodulators, tumour targets, vaccine adjuvants. Enhances production of the NQO1 protein gene that protects against UV radiation by stimulating epidermal keratinocytes and inhibits the accumulation of reactive oxygen species (ROS). It increases the expression of antioxidant proteins and improves the condition of the erythema. 

Glycogen storage disease type I or von Gierke disease is hereditary and affects approximately 1/100k births (2).

Biochemical research

Iodine measurement indicator.

Cosmetics

Used as a moisturiser, it enhances the production of the biomolecule adenosine triphosphate (ATP) that provides energy to cells and boosts ceramide production in primary normal human epidermal keratinocytes (NHEK). Reduces age-induced skin roughness.

For more information:

Glycogen studies

• Molecular Formula     C₂₄H₄₂O₂₁        (C₆H₁₀O₅)n
• Molecular Weight     666.6
• Exact Mass    666.22200
• CAS  9005-79-2
• UNII    309GSC92U1
• EC Number   232-683-8
• DSSTox Substance ID  232-683-8
• IUPAC  (2S,3R,4S,5S,6R)-2-[[(2R,3S,4R,5R,6R)-4,5-dihydroxy-3-[(2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy-6-[(2R,3S,4R,5R,6S)-4,5,6-trihydroxy-2-(hydroxymethyl)oxan-3-yl]oxyoxan-2-yl]methoxy]-6-(hydroxymethyl)oxane-3,4,5-triol
• InChI=1S/C24H42O21/c25-1-5-9(28)11(30)16(35)22(41-5)39-4-8-20(45-23-17(36)12(31)10(29)6(2-26)42-23)14(33)18(37)24(43-8)44-19-7(3-27)40-21(38)15(34)13(19)32/h5-38H,1-4H2/t5-,6-,7-,8-,9-,10-,11+,12+,13-,14-,15-,16-,17-,18-,19-,20-,21+,22+,23-,24-/m1/s1  
• InChl Key      BYSGBSNPRWKUQH-UJDJLXLFSA-N
• SMILES   C(C1C(C(C(C(O1)OCC2C(C(C(C(O2)OC3C(OC(C(C3O)O)O)CO)O)O)OC4C(C(C(C(O4)CO)O)O)O)O)O)O)O
• MDL number  MFCD00081547
• PubChem Substance ID      
• RTECS   MC2700000

Synonyms

• Lyoglycogen
• Phytoglycogen

References______________________________________________________________________

(1) Preiss, J., & Walsh, D. A. (1981). Biology of Carbohydrates. Vol. I.

(2) Turki A, Stockler S, Sirrs S, Salvarinova R, Ho G, Branov J, Rosen-Heath A, Bosdet T, Elango R. Development of minimally invasive 13C-glucose breath test to examine different exogenous carbohydrate sources in patients with glycogen storage disease type Ia. Mol Genet Metab Rep. 2022 May 11;31:100880. doi: 10.1016/j.ymgmr.2022.100880.