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amylopectin

 
Dictionary: am·y·lo·pec·tin   (ăm'ə-lō-pĕk'tĭn) pronunciation
n.
The outer portion of a starch granule consisting of insoluble, highly branched polysaccharides of high molecular weight.


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Chemistry Dictionary: amylopectin
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A polysaccharide comprising highly branched chains of glucose molecules. It is one of the constituents (the other being amylose) of starch.



Food and Nutrition: amylopectin
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The branched chain form of starch. About 75-80% of most starches; the remainder is amylose.

A component of starch consisting of highly branched chains of glucose units.

Veterinary Dictionary: amylopectin
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The insoluble constituent of starch; the soluble constituent is amylose.

Wikipedia: Amylopectin
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Amylopectin
Amylopektin Sessel.svg
Identifiers
CAS number 9037-22-3
EC number 232-911-6
Properties
Molecular formula variable
Molar mass variable
Appearance white powder
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Amylopectin (pronounced /ˌæmɨloʊˈpɛktɨn/) is a polysaccharide and highly branched polymer of glucose found in plants. It is one of the two components of starch, the other being amylose. It is not soluble in water.

Glucose units are linked in a linear way with α(1→4) glycosidic bonds. Branching takes place with α(1→6) bonds occurring every 24 to 30 glucose units. In contrast, amylose contains very few α(1→6) bonds which causes it to be hydrolyzed more slowly but have higher density.

Its counterpart in animals is glycogen which has the same composition and structure, but with more extensive branching that occurs every 8 to 12 glucose units.

Plants store starch within specialized organelles called amyloplasts. When energy is needed for cell work, the plant hydrolyzes the starch releasing the glucose subunits. Humans and other animals that eat plant foods also use amylase, an enzyme that assists in breaking down amylopectin.

Starch is made of about 70% amylopectin by weight, though it varies depending on the source (higher in medium-grain rice till 100% in waxy rice, waxy potato starch and waxy corn and lower in long-grain rice, amylomaize and russet potato, for example). Amylopectin is highly branched, being formed of 2,000 to 200,000 glucose units. Its inner chains are formed of 20-24 glucose subunits.

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Copyrights:

Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.  Read more
Chemistry Dictionary. A Dictionary of Chemistry. Sixth Edition. Copyright © Market House Books Ltd, 2008. All rights reserved.  Read more
Food and Nutrition. A Dictionary of Food and Nutrition. Copyright © 1995, 2003, 2005 by A. E. Bender and D. A. Bender. All rights reserved.  Read more
Sports Science and Medicine. The Oxford Dictionary of Sports Science & Medicine. Copyright © Michael Kent 1998, 2006, 2007. All rights reserved.  Read more
Veterinary Dictionary. Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved.  Read more
Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Amylopectin" Read more