Structure of Glycogens

Biochemical studies follow several themes. For example, investigations can be focussed on the chemical structures of molecules, (for example the structure of glycogen, DNA or protein conformation) or the structural inter-relationship between molecules (e.g. enzymes with their substrates, hormones with their receptors). The other branch of biochemical enquiry is into those numerous dynamic events known collectively as metabolism , defined here as all of the chemical reactions and their associated energy changes occurring within cells . The purpose of metabolism is to provide the... 

Figure 6.21 Structure of glycogen. Reproduced with permission from Boyer, R, Concepts in Biochemistry, John Wiley Sons, 2006.

The branched structure of glycogen allows rapid release of sugar residues. The most... 

Clear discussion of the regulatory changes in the structure of glycogen phosphorylase, based on the structures (from x-ray diffraction studies) of the active and less active forms of the enzyme. 

Maher, George G., The Methyl Ethers of the Aldopentoses and of Rhamnose and Fucose, X, 257-272 Maher, George G., The Methyl Ethers of D-Galactose, X, 273-282 Manners, D. J., The Molecular Structure of Glycogens, XII, 261-298 Marsh, C. A. See Conchie, J. McCloskey, ChesterM., Benzyl Ethers of Sugars, XII, 137-156 McColloch, R. J. See Kertesz, Z. I. McDonald, Emma J., The Polyfructo-... 

Lumsden, R. D. (1965). Macromolecular structure of glycogen in some cyclophyllidean and trypanorhynch cestodes. Journal of Parasitology, 51 501-15. 

The structure of glycogen is similar to that of amylopectin, but with more extensive branching. The highly branched structure of glycogen leaves many end groups available for quick hydrolysis to provide glucose needed for metabolism. 

Figure 21.6. Structure of Glycogen Phosphorylase. This enzyme forms a homodimer one subunit is shown in white and the other in yellow. Each catalytic site includes a pyridoxal-phosphate (PLP) group, linked to lysine 680 of the enzyme. The binding site for the phosphate (Pj) substrate is shown.

Figure 21.16. Structure of Glycogen Transferase. A conserved aspartate residue forms a covalent intermediate with a chain of glucose molecules.

R. Melendez, E. Melendez-Hevia, and E.I. Canela. 1999. The fractal structure of glycogen A clever solution to optimize cell metabolism J. 77 1327-1332. (PubMed)... 

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