digplanet beta 1: Athena
Share digplanet:

Agriculture

Applied sciences

Arts

Belief

Business

Chronology

Culture

Education

Environment

Geography

Health

History

Humanities

Language

Law

Life

Mathematics

Nature

People

Politics

Science

Society

Technology

Not to be confused with Gluconeogenesis or Glycogenolysis.

Glycogenesis is the process of glycogen synthesis, in which glucose molecules are added to chains of glycogen for storage. This process is activated during rest periods following the Cori cycle, in the liver, and also activated by insulin in response to high glucose levels, for example after a carbohydrate-containing meal.

Steps[edit]

Glycogenesis.png
  • Glucose is converted into glucose-6-phosphate by the action of glucokinase or hexokinase.
  • Glucose-6-phosphate is converted into glucose-1-phosphate by the action of phosphoglucomutase, passing through the obligatory intermediate glucose-1,6-bisphosphate.
  • Glucose-1-phosphate is converted into UDP-glucose by the action of the enzyme UDP-glucose phosphorylase. Pyrophosphate is formed, which is later hydrolysed by pyrophosphatase into two phosphate molecules.
  • Glycogenin, a homodimer, has a tyrosine residue on each subunit that serves as the anchor for the reducing end of glycogen. Initially, about eight UDP-glucose molecules are added to each tyrosine residue by glycogenin, forming α(1→4) bonds.
  • Once a chain of eight glucose monomers is formed, glycogen synthase binds to the growing glycogen chain and adds UDP-glucose to the 4-hydroxyl group of the glucosyl residue on the non-reducing end of the glycogen chain, forming more α(1→4) bonds in the process.
  • Branches are made by glycogen branching enzyme (also known as amylo-α(1:4)→α(1:6)transglycosylase), which transfers the end of the chain onto an earlier part via α-1:6 glycosidic bond, forming branches, which further grow by addition of more α-1:4 glycosidic units.

Control and regulations[edit]

Glycogenesis responds to hormonal control.

One of the main forms of control is the varied phosphorylation of glycogen synthase and glycogen phosphorylase. This is regulated by enzymes under the control of hormonal activity, which is in turn regulated by many factors. As such, there are many different possible effectors when compared to allosteric systems of regulation.

Epinephrine (Adrenaline)[edit]

See also: Epinephrine

Glycogen phosphorylase is activated by phosphorylation, whereas glycogen synthase is inhibited.

Glycogen phosphorylase is converted from its less active "b" form to an active "a" form by the enzyme phosphorylase kinase. This latter enzyme is itself activated by protein kinase A and deactivated by phosphoprotein phosphatase-1.

Protein kinase A itself is activated by the hormone adrenaline. Epinephrine binds to a receptor protein that activates adenylate cyclase. The latter enzyme causes the formation of cyclic AMP from ATP; two molecules of cyclic AMP bind to the regulatory subunit of protein kinase A, which activates it allowing the catalytic subunit of protein kinase A to dissociate from the assembly and to phosphorylate other proteins.

Returning to glycogen phosphorylase, the less active "b" form can itself be activated without the conformational change. 5'AMP acts as an allosteric activator, whereas ATP is an inhibitor, as already seen with phosphofructokinase control, helping to change the rate of flux in response to energy demand.

Epinephrine not only activates glycogen phosphorylase but also inhibits glycogen synthase. This amplifies the effect of activating glycogen phosphorylase. This inhibition is achieved by a similar mechanism, as protein kinase A acts to phosphorylate the enzyme, which lowers activity. This is known as co-ordinate reciprocal control. Refer to glycolysis for further information of the regulation of glycogenesis.

Insulin[edit]

See also: Insulin

Insulin has an antagonistic effect to epinephrine signaling via the beta-adrenergic receptor (G-Protein coupled receptor). When insulin binds to its receptor (insulin receptor), it results in the activation (phosphorylation) of Akt which in turn activates Phosphodiesterase (PDE). PDE then will inhibit cyclic AMP (cAMP) action and cause inactivation of PKA which will cause Hormone Sensitive Lipase (HSL) to be dephosphorylated and inactive so that lipolysis and lipogenesis is not occurring simultaneously.

Calcium ions[edit]

Calcium ions or cyclic AMP (cAMP) act as secondary messengers. This is an example of negative control. The calcium ions activate phosphorylase kinase. This activates glycogen phosphorylase and inhibits glycogen synthase.

See also[edit]

External links[edit]


Original courtesy of Wikipedia: http://en.wikipedia.org/wiki/Glycogenesis — Please support Wikipedia.
This page uses Creative Commons Licensed content from Wikipedia. A portion of the proceeds from advertising on Digplanet goes to supporting Wikipedia.
3061 videos foundNext > 

Glycogenesis

www.SalmonellaPlace.com This is a tutorial/lecture on Glycogenesis. We cover some topics important for classes such as Biology, Biochemistry, Physiology, etc.

Overview of Glycogenesis

Donate here: http://www.aklectures.com/donate.php Website video: http://www.aklectures.com/lecture/overview-of-glycogenesis Facebook link: ...

Glycogenesis

Human Metabolism Map II - Gluconeogenesis & Glycogenesis

http://armandoh.org/ http://www.facebook.com/ArmandoHasudungan Song: Angus & Julia Stone - Devil's Tears Image: ...

glycogenesis

glycogenesis.

Glycogenesis

Dr. Pepper delivers the basics on the glycogenesis pathway.

Animation of Glycogenesis

In order to store glycogen, the cell can undergo glycogenesis. This leads to long chains of glycogen molecules. The process of glycogenesis is more thoroughly ...

Insulin and Glucose Regulation of Glycogenesis

Donate here: http://www.aklectures.com/donate.php Website video: http://www.aklectures.com/lecture/insulin-and-glucose-regulation-of-glycogenesis Facebook ...

Glycogen (Part 2 of 4) - Glycogen Synthesis

Welcome to Moof University! My name is Mahfoud, and I recently graduated from UC Riverside. I've made these videos to help students with introductory ...

Glycogenesis lecture by Dr. Bon

Glycogenesis lecture by Dr. Bon.

3061 videos foundNext > 

31 news items

Nature.com

Nature.com
Tue, 19 Jan 2016 07:01:49 -0800

Central carbon metabolism and other relevant metabolic pathways identified in SAR11 genomes. Glycogenesis, TCA cycle and glyoxylate shunt are shown in the center of the plot with adjunction pathways to either side such as the pentose phosphate and ED ...

Sydney Morning Herald

Sydney Morning Herald
Tue, 12 Jan 2016 05:15:17 -0800

Health experts are dismayed that summer smoothies marketed as "98 per cent fat free" and "with an abundance of nutrition" contain more kilojoules than a Big Mac, and are urging consumers to steer clear. A survey of 40 popular smoothies, frappes and ...

OregonLive.com

OregonLive.com
Thu, 25 Jun 2015 09:07:30 -0700

In their study with rats, the Chinese scientists tried to counter this build-up in the liver by supercharging the gene. "PPP1r3G is a regulatory subunit of protein phosphatase 1 and stimulates glycogenesis in the liver," the study states. "Chronic and ...
 
BMC Blogs Network
Mon, 12 Oct 2015 17:56:15 -0700

Bacterial infections comprise a global health challenge as the incidences of antibiotic resistance increase. Pathogenic potential of bacteria has been shown to be context dependent, varying in response to environment and even within the strains of the ...
 
The Hindu
Sun, 26 Jul 2015 17:16:05 -0700

Cinnamon can reduce blood glucose via reduction of insulin resistance and increase of hepatic glycogenesis, she said. Turmeric and garlic. Dr. Latha said turmeric has been used for the treatment of diabetes in Ayurveda and traditional Chinese medicine.

h+ Magazine

h+ Magazine
Thu, 12 Mar 2015 14:12:01 -0700

This established that the mechanism of the treatment of lung tumours with citreoviridin, an inhibitor of ectopic ATP synthase, was due to proteins involved in glycogenesis which increases in lung tumours and whose inhibition reduces their proliferation ...

Yahoo News

Yahoo News
Thu, 10 Apr 2014 10:23:24 -0700

But don't stuff your face with every carb-heavy food in your cabinet. You need to carefully craft your carb consumption. Glycogenesis is the process of storing carbs as energy. This energy source (muscle glycogen) is important to athletic performance ...

LiveScience.com

LiveScience.com
Mon, 31 Mar 2014 13:22:44 -0700

As the small intestine absorbs glucose, the pancreas releases insulin, which stimulates body tissues and causes them to absorb this glucose and metabolize it (a process known as glycogenesis). This stored glucose (glycogen) is used to maintain healthy ...
Loading

Oops, we seem to be having trouble contacting Twitter

Support Wikipedia

A portion of the proceeds from advertising on Digplanet goes to supporting Wikipedia. Please add your support for Wikipedia!

Searchlight Group

Digplanet also receives support from Searchlight Group. Visit Searchlight