Glycogen metabolism (WP1388)

Danio rerio

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].


Alex Pico , Christine Chichester , Egon Willighagen , Martina Summer-Kutmon , Denise Slenter , Elisa Cirillo , and Eric Weitz


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Danio rerio



Pathway Ontology

glycogen metabolic pathway


Label Type Compact URI Comment
Glycogen Metabolite chebi:28087
cAMP Metabolite hmdb:HMDB0000058
Glycogen (n+1) Metabolite chebi:28087
Glucose-1-phosphate Metabolite chebi:29042
UDP-glucose Metabolite hmdb:HMDB0000286
Glucose 1-phosphate Metabolite hmdb:HMDB0001586
Glycogen Metabolite chebi:28087
Glucose Metabolite chebi:17634
Glycogen (n+1) Metabolite chebi:28087
Glucose-6-phosphate Metabolite hmdb:HMDB0001401
pygma GeneProduct ncbigene:553655
ppp2cb GeneProduct ncbigene:406582
LOC569706 GeneProduct ncbigene:569706
gys2 GeneProduct ncbigene:373082
LOC562282 GeneProduct ncbigene:562282
phkg2 GeneProduct ncbigene:393937
ppp2r5c GeneProduct ncbigene:557208
PHKA1 GeneProduct ncbigene:572183
zgc:123166 GeneProduct ncbigene:100002802
pygb GeneProduct ncbigene:403051
LOC554439 GeneProduct ncbigene:554439
GSK3A GeneProduct ncbigene:30664
DKEYP-38B6.1 GeneProduct ncbigene:565849
PPP2R1A GeneProduct ncbigene:406685
ppp2r5eb GeneProduct ncbigene:373878
zgc:56064 GeneProduct ncbigene:393885
zgc:77529 GeneProduct ncbigene:406610
LOC100001644 GeneProduct ncbigene:100001644
agl GeneProduct ncbigene:567798
ppp2r5a GeneProduct ncbigene:562460
im:6895423 GeneProduct ncbigene:566032
LOC556199 GeneProduct ncbigene:556199
ppp2r2d GeneProduct ncbigene:327263
gsk3b GeneProduct ncbigene:30654
ppp2r1b GeneProduct ncbigene:449548
LOC559212 GeneProduct ncbigene:559212
pgm1 GeneProduct ncbigene:394000
ppp2r4 GeneProduct ncbigene:445031
PYGL GeneProduct ncbigene:493916