Glycogen metabolism (WP317)

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 [http://en.wikipedia.org/wiki/Glycogen Wikipedia].
last edited

Authors

Kdahlquist, MaintBot, M.Braymer, AlexanderPico, AdrienDefay, Christine Chichester, Mkutmon, and Eweitz

Cited In

Organism

Mus musculus

Communities

Annotations

Pathway Ontology: glycogen metabolic pathway

Participants

Label Type Compact Identifier
Pygm GeneProduct ncbigene:19309
Ppp2cb GeneProduct ncbigene:19053
Phkb GeneProduct ncbigene:102093
Gys2 GeneProduct ncbigene:232493
Ppp2r5b GeneProduct ncbigene:225849
Phkg2 GeneProduct ncbigene:68961
Glycogen Metabolite hmdb:HMDB0000757
Ppp2r5c GeneProduct ncbigene:26931
Calm1 GeneProduct ncbigene:12313
cAMP Metabolite hmdb:HMDB0000058
Phka1 GeneProduct ncbigene:18679
Ppp2r2c GeneProduct ncbigene:269643
Pygb GeneProduct ncbigene:110078
Ugp2 GeneProduct ncbigene:216558
Glycogen (n+1) Metabolite hmdb:HMDB0000757
Glucose 1-phosphate Metabolite hmdb:HMDB0001586
Glycolysis Pathway wikipathways:WP157
Gys1 GeneProduct ncbigene:14936
Gsk3a GeneProduct ncbigene:606496
3222402P14Rik GeneProduct ncbigene:235542
Gyg GeneProduct ncbigene:27357
Ppp2r1a GeneProduct ncbigene:51792
Calm3 GeneProduct ncbigene:12315
Ppp2r5e GeneProduct ncbigene:26932
Ppp2ca GeneProduct ncbigene:19052
Ugp2 GeneProduct ncbigene:216558
UDP-glucose Metabolite hmdb:HMDB0000286
GYG2 GeneProduct None
Ppp2r5d GeneProduct ncbigene:21770
Ppp2r2b GeneProduct ncbigene:72930
Glucose 1-phosphate Metabolite hmdb:HMDB0001586
Glycogen Metabolite hmdb:HMDB0000757
Glucose Metabolite hmdb:HMDB0000122
Agl GeneProduct ncbigene:77559
Ppp2r5a GeneProduct ncbigene:226849
Calm2 GeneProduct ncbigene:12314
PPP2R3B GeneProduct None
Phka2 GeneProduct ncbigene:110094
Ppp2r2a GeneProduct ncbigene:71978
Glycogen (n+1) Metabolite hmdb:HMDB0000757
Gsk3b GeneProduct ncbigene:56637
Phkg1 GeneProduct ncbigene:18682
Ppp2r1b GeneProduct ncbigene:73699
Gbe1 GeneProduct ncbigene:74185
Pgm2 GeneProduct ncbigene:72157
Glucose 6-phosphate Metabolite hmdb:HMDB0001401
Ppp2r4 GeneProduct ncbigene:110854
Pygl GeneProduct ncbigene:110095

References