Glycogen metabolism (WP436)

Caenorhabditis elegans

Glycogen is a very large, branched polymer of glucose residues. Within skeletal muscle and liver glucose is stored as glycogen. In the liver, glycogen synthesis and degradation are regulated to maintain blood-glucose levels as required to meet the needs of the organism as a whole. In contrast, in muscle, these processes are regulated to meet the energy needs of the muscle itself. '''Glycogen synthesis''' is, unlike its breakdown, endergonic. This means that glycogen synthesis requires the input of energy. Energy for glycogen synthesis comes from UTP, which reacts with glucose-1-phosphate, forming UDP-glucose, in reaction catalyzed by UDP-glucose pyrophosphorylase. Glycogen is synthesized from monomers of UDP-glucose by the enzyme glycogen synthase, which progressively lengthens the glycogen chain with (a1->4) bonded glucose. As glycogen synthase can only lengthen an existing chain, the protein glycogenin is needed to initiate the synthesis of glycogen. The glycogen-branching enzyme, amylo (a1->4) to (a1->6) transglycosylase, catalyzes the transfer of a terminal fragment of 6-7 glucose residues from a nonreducing end to the C-6 hydroxyl group of a glucose residue deeper into the interior of the glycogen molecule. The branching enzyme can act upon only a branch having at least 11 residues, and the enzyme may transfer to the same glucose chain or adjacent glucose chains. '''Glycogen degradation''' consists of three steps: (1) the release of glucose 1-phosphate from glycogen, (2) the remodeling of the glycogen substrate to permit further degradation, and (3) the conversion of glucose 1-phosphate into glucose 6-phosphate for further metabolism. Information partly derived from "Biochemistry" by Stryer and [ Wikipedia].


Kdahlquist , Alex Pico , Christine Chichester , Martina Summer-Kutmon , Eric Weitz , and Friederike Ehrhart


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Caenorhabditis elegans



Pathway Ontology

glycogen metabolic pathway


Label Type Compact URI Comment
ALPHA-D-GLUCOSE-1-PHOSPHATE Metabolite chebi:29042
cAMP Metabolite chebi:17489
Glycogen Metabolite chebi:28087
ALPHA-D-GLUCOSE-6-PHOSPHATE Metabolite chebi:17665
glucose Metabolite chebi:17234
UDP-glucose Metabolite chebi:18066
Glycogen Metabolite chebi:28087
C14B9.8 GeneProduct ncbigene:176149
Y50D7A.3 GeneProduct ncbigene:190101
gsy-1 GeneProduct ncbigene:174924
K08E3.5 GeneProduct ncbigene:176814
R06A4.8 GeneProduct ncbigene:175091
gsk-3 GeneProduct ncbigene:173149
paa-1 GeneProduct ncbigene:175750
W08G11.4 GeneProduct ncbigene:180100
Y67D8A.1 GeneProduct ncbigene:177094
glycogenin GeneProduct ncbigene:180644
sur-6 GeneProduct ncbigene:172826
Y71H2AM.20 GeneProduct ncbigene:175395
let-92 GeneProduct ncbigene:178117
calmodulin GeneProduct ncbigene:178614
T22F3.3 GeneProduct ncbigene:178777
T04A8.7 GeneProduct ncbigene:3565201
K08E3.5 GeneProduct ncbigene:176814
C06G1.5 GeneProduct ncbigene:181721
glycogenin GeneProduct ncbigene:180119
phosphoglucomutase GeneProduct ncbigene:173843
C13G3.3 GeneProduct ncbigene:179526