Glycogenolysis (also known as "Glycogenlysis") is the catabolism of glycogen by removal of a glucose monomer through cleavage with inorganic phosphate to produce glucose-1-phosphate. This derivative of glucose is then converted to glucose-6-phosphate, an intermediate in glycolysis.

The hormones glucagon and epinephrine stimulate glycogenolysis.


Glycogenolysis transpires in the muscle and liver tissue, where glycogen is stored, as a hormonal response to epinephrine (e.g., adrenergic stimulation) and/or glucagon, a pancreatic peptide triggered by low blood glucose concentrations.

* Liver (hepatic) cells can consume the glucose-6-phosphate in glycolysis, or remove the phosphate group using the enzyme glucose-6-phosphatase and release the free glucose into the bloodstream for uptake by other cells.

* Muscle cells in humans do not possess glucose-6-phosphatase and hence will not release glucose, but instead use the glucose-6-phosphate in glycolysis.

Clinical significance

Parenteral (intravenous) administration of glucagon is a common human medical intervention in diabetic emergencies when sugar cannot be given orally.


First step

The overall reaction for the 1st step is:

Glycogen (n residues) + Pi <-----> Glycogen (n-1 residues)+ G1P

Here, glycogen phosphorylase cleaves the bond at the 1 position by substitution of a phosphoryl group. It breaks down glucose polymer at α-1-4 linkages until 5 linked glucoses are left on the branch. (Furthermore, glycogen phosphorylase (EC can be used as a marker enzyme to determine glycogen breakdown. )

econd step

The 2nd step involves the debranching enzyme that moves the remaining glucose units to another non-reducing end. This results in more glucose units available to glycogen phosphorylase. (step 1) The final action of the debranching enzyme leads to the original glucose 1-P connected 1,4 to another branch being released.

Third step

The 3rd and last stage converts G1P (glucose-1-phosphate) to G6P (glucose-6-phosphate) through the enzyme phosphoglucomutase.


The key regulatory enzyme of the process of glycogenolysis is Glycogen phosphorylase:
* Phosphorylation --> activation
* Dephosphorylation --> inhibition

External links

* [ The chemical logic of glycogen degradation at]

Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать курсовую

Look at other dictionaries:

  • glycogenolysis — glikogenolizė statusas T sritis chemija apibrėžtis Metabolinis glikogeno skaidymas. atitikmenys: angl. glycogenolysis rus. гликогенолиз …   Chemijos terminų aiškinamasis žodynas

  • glycogenolysis — noun (plural glycogenolyses) Etymology: New Latin Date: 1909 the breakdown of glycogen especially to glucose in the animal body • glycogenolytic adjective …   New Collegiate Dictionary

  • glycogenolysis — n. [Gr. glykys, sweet; genes, born; lyein, to break up] The breakdown of glycogen …   Dictionary of invertebrate zoology

  • glycogenolysis — gly·co·gen·ol·y·sis (glī kə jə nŏlʹĭ sĭs) n. pl. gly·co·gen·ol·y·ses ( sēz ) The biochemical breakdown of glycogen to glucose.   gly co·gen o·lytʹic ( jĕn ə lĭtʹĭk) adj. * * * …   Universalium

  • glycogenolysis — noun The production of glucose 1 phosphate by splitting a glucose monomer from glycogen using inorganic phosphate See Also: glycogenolytic …   Wiktionary

  • glycogenolysis — The hydrolysis of glycogen to glucose. * * * gly·co·gen·ol·y·sis .glī kə jə näl ə səs n, pl y·ses .sēz the breakdown of glycogen esp. to glucose in the animal body compare GLYCOGENESIS gly·co·gen·o·lyt·ic jən əl it ik, .jen …   Medical dictionary

  • glycogenolysis — n. breaking down of glycogen into glucose through enzymatic activity (Chemistry) …   English contemporary dictionary

  • glycogenolysis — gly·co·gen·ol·y·sis …   English syllables

  • glycogenolysis — n. a biochemical process, occurring chiefly in the liver and in muscle, by which glycogen is broken down into glucose …   The new mediacal dictionary

  • glycogenolysis — /ˌglaɪkoʊdʒəˈnɒləsəs/ (say .gluykohjuh noluhsuhs) noun the hydrolysis of glycogen to glucose …  

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”