Key Difference – Amylopectin vs Glycogen
Polysaccharides are large polymers made from ten to thousands of monomers linked together by glycosidic bonds. Amylopectin and glycogen are two such polysaccharides found in plants and animals, respectively. Both these polysaccharides are good energy sources. Our body needs a continuous energy supply to perform bodily functions. Most of the energy derived from these two polysaccharides are utilized by humans for their daily energy requirements. Amylopectin and glycogen are similar in their structure as both are made from α D glucose monomers. The key difference between amylopectin and glycogen is, amylopectin is an insoluble form of starch while glycogen is a soluble form of starch.
CONTENTS
1. Overview and Key Difference
2. What is Amylopectin
3. What is Glycogen
4. Side by Side Comparison – Amylopectin vs Glycogen
5. Summary
What is Amylopectin?
Amylopectin is a polysaccharide found mostly in plants. It is a branched chain polysaccharide in which glucose monomers are joined together mainly by α 1 – 4 glycosidic linkages and occasionally by α 1- 6 glycosidic linkages. Alpha 1 – 6 linkages are responsible for the branching nature of amylopectin. One molecule of amylopectin may contain thousands of glucose monomers. The length of the amylopectin chain can be ranged between 2000 – 200,000 glucose monomers. Hence, it has a larger molecular weight.
Amylopectin is insoluble in water. Amylopectin is produced by plants and it accounts for 80% of plant starch. It is stored in their fruits, seeds, leaves, stems, roots, etc. Generally, amylopectin can be known as plant starch.
Amylopectin is a good energy source for human and animals. Our brain needs a good supply of glucose for its functions. Glycogen together with amylopectin provides glucose to blood and to or brain.
Figure 01: Amylopectin Structure
What is Glycogen?
Glycogen is a highly branched polysaccharide found in animals. In all mammalian cells, glucose is stored in the form of glycogen. However, glycogen is most abundant in liver cells and secondly in muscle cells. Glycogen is also known as animal starch and is considered as a primary energy source of animals. Glycogen is a large polymer composed of glucose monomers. The highly branching structure of glycogen is supported by two linkages such as α 1- 4 glycosidic bonds and α 1- 6 glycosidic bonds between glucose monomers. Compared to amylopectin, glycogen structure is highly branched due to comparatively abundant α 1 -6 glycosidic linkages between glucose chains.
Animal foods are good sources of glycogen. When you eat glycogen, it is converted into glucose and becomes a good source of energy. The liver is important for maintaining blood glucose at a proper level by storing and breaking glycogen. When blood glucose level is too low, glycogen is catabolized into glucose and released into the blood. Glycogen break down is known as glycogenolysis. When excess glucose is there, glucose convert into glycogen and store in the liver and muscle cells. This process is known as glycogenesis. These two processes are signaled by two hormones named insulin and glucagon. The catabolic process which splits glycogen into glucose is known as glycogenolysis.
Figure 02: Glycogen Structure
What is the difference between Amylopectin and Glycogen?
Amylopectin vs Glycogen |
|
| Amylopectin is a polysaccharide composed of glucose monomers. | Glycogen is a polysaccharide which forms glucose on hydrolysis. |
| Form of Starch | |
| Amylopectin is the insoluble form of starch. | Glycogen is the soluble form of starch. |
| Found in | |
| Amylopectin is found mostly in plants; hence referred as plant starch. | Glycogen is found in animals. |
| Branching | |
| Amylopectin is less branched compared to glycogen. | Glycogen is a highly branched molecule. |
| Branch Size |
|
| Branches are larger in amylopectin compared to glycogen. | Branches are shorter compared to amylopectin. |
Summary – Amylopectin vs Glycogen
Amylopectin and glycogen are two forms of starch found in plants and animals respectively. Both are polysaccharides composed of glucose monomers. Amylopectin and glycogen are branched chains. Glycogen is highly branched compared to amylopectin. Amylopectin is insoluble in water while glycogen is soluble in water. This is the main difference between amylopectin and glycogen. Both these polysaccharides are good energy sources for humans and animals. They are very much similar in structure. Glycogen is produced in the liver cells as well and is predominately abundant in liver cells and skeletal muscle cells in animals.
Reference:
1. Berg, Jeremy M. “Glycogen Metabolism.” Biochemistry. 5th edition. U.S. National Library of Medicine, 01 Jan. 1970. Web. 09 May 2017
2. “Differences Between Amylopectin and Glycogen.” Difference Between. N.p., 21 Dec. 2012. Web. 09 May 2017. <http://www.differencebetween.net/science/health/differences-between-amylopectin-and-glycogen/>.
3.”14.7: Polysaccharides.” Chemistry LibreTexts. Libretexts, 14 Oct. 2016. Web. 09 May 2017. <https://chem.libretexts.org/Under_Construction/Textmaps_and_Wikitexts/MVC%3A_Chem_1406/Chapters/14%3A_Carbohydrates/14.7%3A_Polysaccharides>.
Image Courtesy:
1.”Glykogen glycosidic bond” By Glykogen.svg: NEUROtikerderivative work: Marek M (talk) – Glykogen.svg (Public Domain) via Commons Wikimedia
2. “Figure 03 02 06” By CNX OpenStax – (CC BY 4.0) via Commons Wikimedia