(biochemistry) The inactive precursor of an enzyme; liberates an active enzyme on reaction with an appropriate kinose. Also known as proenzyme.
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(biochemistry) The inactive precursor of an enzyme; liberates an active enzyme on reaction with an appropriate kinose. Also known as proenzyme.
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Britannica Concise Encyclopedia:
zymogen |
For more information on zymogen, visit Britannica.com.
Oxford Food & Nutrition Dictionary:
zymogens |
The inactive form in which some enzymes, especially the protein digestive enzymes, are secreted, being activated after secretion. Also called pro-enzymes, or enzyme precursors.
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zymogen |
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Oxford Dictionary of Biochemistry:
zymogen |
| zymase, zygotene, zygote | |
| zymogen granule, zymogram, zymology |
Saunders Veterinary Dictionary:
zymogen |
An inactive precursor that is converted into an active enzyme by action of an acid or another enzyme or by other means; a proenzyme.
Wikipedia on Answers.com:
Zymogen |
A zymogen (or proenzyme) is an inactive enzyme precursor. A zymogen requires a biochemical change (such as a hydrolysis reaction revealing the active site, or changing the configuration to reveal the active site) for it to become an active enzyme. The biochemical change usually occurs in a lysosome where a specific part of the precursor enzyme is cleaved in order to activate it. The inactivating piece which is cleaved off can be a peptide unit, or can be independently folding domains comprising more than 100 residues. Although they limit the enzymes ability, these n-terminal extensions of the enzyme or a “prosegment” often aid in the stabilizing and folding of the enzyme they inhibit.
The pancreas secretes zymogens partly to prevent the enzymes from digesting proteins in the cells in which they are synthesised. Enzymes like pepsin are created in the form of pepsinogen, an inactive zymogen. Pepsinogen is activated when Chief cells release it into HCl which partially activates it. Another partially activated pepsinogen completes the activation by removing the peptide turning the pepsinogen into pepsin. Accidental activation of zymogens can happen when the secretion duct in the pancreas is blocked by a gal stone resulting in acute pancreatitis.
Fungi also secrete digestive enzymes into the environment as zymogens. The external environment has a different pH than inside the fungal cell and this changes the zymogen's structure into an active enzyme.
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![]() | McGraw-Hill Science & Technology Dictionary. McGraw-Hill Dictionary of Scientific and Technical Terms. Copyright © 2003, 1994, 1989, 1984, 1978, 1976, 1974 by McGraw-Hill Companies, Inc. All rights reserved. Read more |
![]() | Britannica Concise Encyclopedia. Britannica Concise Encyclopedia. © 1994-2012 Encyclopædia Britannica, Inc. All rights reserved. Read more | |
![]() | Oxford Food & Nutrition Dictionary. A Dictionary of Food and Nutrition. Copyright © 1995, 2003, 2005 by A. E. Bender and D. A. Bender. All rights reserved. Read more | |
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| Oxford Dictionary of Biochemistry. Oxford University Press. Oxford Dictionary of Biochemistry and Molecular Biology © 1997, 2000, 2006 All rights reserved. Read more | ||
![]() | Saunders 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 | |
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![]() | Wikipedia on Answers.com. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article Zymogen. Read more |
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