Salivary amylase
| Salivary amylase | ||
|---|---|---|
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| Belt model according to PDB 1SMD | ||
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Existing structural data: s. UniProt |
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| Mass / length primary structure | 496 amino acids | |
| Secondary to quaternary structure | Monomer | |
| Cofactor | Calcium, chloride | |
| Identifier | ||
| Gene name (s) | AMY1A , AMY1B , AMY1C | |
| External IDs |
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| Drug information | ||
| ATC code | A09 AA01 | |
| Enzyme classification | ||
| EC, category | 3.2.1.1 , glycosidase | |
| Response type | Hydrolysis of 1,4-α-D-glycoside bonds | |
| Substrate | Starch, glycogen and similar oligo- or polysaccharides | |
| Products | Maltose, maltotriose | |
| Occurrence | ||
| Homology family | alpha-amylase | |
| Parent taxon | Creature | |
Salivary amylase (also α-amylase 1 , Ptyalin ) hot three enzyme - isoforms , the man in saliva are produced. It is the enzyme in all living things that is able to break down storage carbohydrates such as starch and glycogen into its constituent parts via the separation of 1,4-α-D-glycoside bonds. In many vertebrates , including humans, carbohydrate digestion begins with the production of the enzyme in saliva .
Two other isoforms are produced by the pancreas , these are called pancreatic amylase .
The genes responsible for coding the isoforms are named AMY1A , AMY1B and AMY1C . They differ only slightly from each other. According to the latest research, isoforms were formed by copying, and only recently. It is the first example of genetic adaptation to changed living and eating habits in humans.
Catalyzed reaction
-alpha-D-Glucose.svg)
(n large) + H 2 O
⇒ (n small)
+ (n small) + ...
Starch, also known as poly-D-glucose, is crushed from the inside out until only maltose and maltotriose are left. In small amounts, maltotriose is split into maltose and glucose. The enzyme is also able to deal with 1-6 branched sugar chains ( amylopectin ); the additional end products are limit dextrins . Starch digestion by salivary amylase is a popular school experiment.
Interactions
The ptyalin formed in the mouth is used to break down the starch. This breakdown process can be severely hindered by certain foods, such as fruits that contain fruit acids, or juices that are drunk too quickly - without salivation. As a result of insufficient separation of strength by inactivating the ptyalin can cause fermentation processes of starch in the gastrointestinal tract and resulting symptoms such as bloating ( flatulence ) come.
Individual evidence
- ↑ UniProt P04745
- ↑ Perry GH, Dominy NJ, Claw KG, et al : Diet and the evolution of human amylase gene copy number variation . In: Nat. Genet. . 39, No. 10, October 2007, pp. 1256-60. doi : 10.1038 / ng2123 . PMID 17828263 . PMC 2377015 (free full text).
- ↑ Hofmann, Eberhard: Biochemistry systematically . 4th edition UNI-MED-Verlag, Bremen 2006, ISBN 3-89599-164-3 .
- ↑ D'Eustachio / Nichols / reactome.org: Digestion of linear starch (amylose) by extracellular amylase
- ↑ D'Eustachio / Nichols / reactome.org: Digestion of branched starch (amylopectin) by extracellular amylase
- ↑ Klaus Ruppersberg: Starch digestion by saliva - what does that actually result? A simple maltose detection at the end of the enzymatic hydrolysis of amylose and the surprising presence of glucose in a ratio of 1:15 . In: MNU Journal . tape 69 , no. 5 . Verlag Klaus Seeberger, 2016, ISSN 0025-5866 , p. 325–328 ( pedocs.de [accessed January 22, 2019]).
