What is the monomer of glycogen
Molecular formula of the repeating unit: C6H10O5
As Glycogen this is the name given to the storage form of carbohydrates present in the human and animal organism, which is comparable to vegetable starch.
Glycogen is a highly cross-linked polymer made of 1,4- and 1,6-glycosidically linked D-glucose molecules, which is therefore also known as a dendrimer.
The synthesis of a glycogen molecule begins with the primer enzyme glycogenin. It's at the center of every glycogen molecule. Glycogenin attaches itself to short polysaccharide chains made of α-1,4-glycosidically bound glucose, which serve as a starting point for glycogen synthase. The glycogen synthase cannot determine this starting point itself - it always orientates itself on an existing chain of glucose molecules.
The glycogen synthase does not use free glucose for polymer formation, but activated UDP-glucose. It is obtained from glucose-6-phosphate by phosphoglucomutase and UTP-glucose-1-phosphate uridylyl transferase. Here, glucose-6-phosphate is firstly converted to glucose-1-phosphate isomerized and then UDP is added:
The glycogen synthase then attaches the UDP-glucose to the primer or the existing glycogen chain, whereby the UDP is released again:
|Glycogen (n glucose) + UDP-glucose → glycogen (n + 1 glucose) + UDP|
The growing glycogen chain does not continue in a strictly linear manner. Every 7 to 12 glucose units it is cut by the 1,4-α-glucan-branching enzyme ("branching enzyme") and the alpha-1,6-glycosidic fragment is attached to the side of the existing chain or an adjacent chain.
see main article:Glycogen synthesis
The breakdown of glycogen is known as glycogenolysis. It behaves almost as a mirror image of the synthesis. The linear glucose chains of the glycogen are broken down by the enzyme glycogen phosphorylase. It catalyzes the bonding of a phosphate group on the C1 atom of glucose. The reaction is dependent on pyridoxal phosphate. The alpha-1,4-glycosidic bond between the glucose molecules is split and glucose-1-phosphate is released. Glucose-1-phosphate is then isomerized to glucose-6-phosphate by a mutase.
Due to the branched structure of the glycogen, another enzyme is necessary in order to also be able to dissolve glucose chains bound by alpha-1,6-glycosides. The glycogen phosphorylase can only break down glycogen up to the fourth glucose molecule before a 1,6 branch. This is the debranching enzyme. This "debranching enzyme" is a bifunctional enzyme that combines two different catalytic activities. On the one hand, it decouples 3 of 4 glucose residues from the remaining short chain and transfers them linearly to an adjacent chain. On the other hand, it splits off the remaining alpha-1,6-glycosidically bound glucose molecule in a second step, with free glucose being formed.
Due to these conversion reactions, around 90% glucose-1-phosphate and around 10% free glucose are produced during glycogen breakdown, because only about every tenth glucose molecule is at a branching point.
see main article: Glycogenolysis
Glycogen can be synthesized and stored in many tissues, including the liver, muscles, kidneys, brain, uterus, and vagina. However, due to the presence of the enzyme glucose-6-phosphatase, only the liver and kidneys are able to mobilize the carbohydrates (approx. 100 g) stored in their parenchyma and make them available to the body again.
Pathophysiologically, increased glycogen storage plays a role in the context of glycogenoses.
- How is Sir Rajnikanth doing in real life
- Why is San Francisco so popular
- Can meditation heal the eyesight
- How do you round off in Java
- How can toner harm your face
- Is Shri Rahul Gandhi married or not
- What is the procedure for TIG welding
- What is special about the HEVC H265
- What kind of airline is Emirates
- What is a bobber motorcycle
- Was Hitler so good for his country
- Are human rights dead
- Are all INTJs antisocial or awkward?
- Why do you love literature
- What is the color of the dark
- Is war necessary for peace
- What does ISIS think about Vietnam
- Whose freedom does the constitution protect?
- What is moral relativism
- What is PPW in content writing
- Supports Spyder Django projects
- How do I introduce Romania
- Like Donald Trump, like Omarosa
- What's your rating of Kingfisher beer