Amylase
| Alpha-amylase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
ExPASy NiceZyme view | | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| Gene Ontology | AmiGO / QuickGO | ||||||||
| |||||||||
| Beta-amylase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
ExPASy NiceZyme view | | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| Gene Ontology | AmiGO / QuickGO | ||||||||
| |||||||||
| Gamma-amylase. Glucan 1,4-alpha-glucosidase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| Gene Ontology | AmiGO / QuickGO | ||||||||
| |||||||||
An amylase (
Classification
| α-amylase | β-amylase | γ-amylase | |
|---|---|---|---|
| Source | Animals, plants, microbes | Plants, microbes | Animals, microbes |
| Tissue | Salivary gland, pancreas | Seeds, fruits | Small intestine |
| Cleavage site | Random α-1,4 glycosidic bond | Second α-1,4 glycosidic bond | Last α-1,4 glycosidic bond |
| Reaction products | Maltose, dextrin, etc. | Maltose | Glucose |
| Optimum pH | 6.7–7.0 | 5.4–5.5 | 4.0–4.5 |
| Optimum temperature in brewing | 68–74 °C (154–165 °F) | 58–65 °C (136–149 °F) | 63–68 °C (145–155 °F) |
α-Amylase
The α-amylases (
Because it can act anywhere on the
In human physiology, both the salivary and pancreatic amylases are α-amylases.
The α-amylase form is also found in plants, fungi (
β-Amylase
Another form of amylase, β-amylase (
Both α-amylase and β-amylase are present in seeds; β-amylase is present in an inactive form prior to
γ-Amylase
γ-Amylase (EC 3.2.1.3 ) (alternative names: Glucan 1,4-a-glucosidase; amyloglucosidase; exo-1,4-α-glucosidase; glucoamylase; lysosomal α-glucosidase; 1,4-α-D-glucan glucohydrolase) will cleave α(1–6) glycosidic linkages, as well as the last α-1,4 glycosidic bond at the nonreducing end of amylose and amylopectin, yielding glucose. The γ-amylase has the most acidic optimum pH of all amylases because it is most active around pH 3. They belong to a variety of different GH families, such as glycoside hydrolase family 15 in fungi, glycoside hydrolase family 31 of human MGAM, and glycoside hydrolase family 97 of bacterial forms.
Uses
Fermentation
α- and β-amylases are important in
In some historic methods of producing alcoholic beverages, the conversion of starch to sugar starts with the brewer chewing grain to mix it with saliva.[5] This practice continues to be practiced in home production of some traditional drinks, such as chhaang in the Himalayas, chicha in the Andes and kasiri in Brazil and Suriname.
Flour additive
Amylases are used in
α-Amylase is often listed as an ingredient on commercially package-milled flour. Bakers with long exposure to amylase-enriched flour are at risk of developing dermatitis[7] or asthma.[8]
Molecular biology
In
Medical uses
Amylase also has medical applications in the use of
Other uses
An inhibitor of alpha-amylase, called phaseolamin, has been tested as a potential diet aid.[10]
When used as a
Bacilliary amylase is also used in clothing and dishwasher detergents to dissolve starches from fabrics and dishes.
Factory workers who work with amylase for any of the above uses are at increased risk of occupational asthma. Five to nine percent of bakers have a positive skin test, and a fourth to a third of bakers with breathing problems are hypersensitive to amylase.[11]
Hyperamylasemia
A January 2007 study from
History
In 1831,
it was named after the Ancient Greek name for saliva: πτύαλον - ptyalon.The modern history of enzymes began in 1833, when French chemists Anselme Payen and Jean-François Persoz isolated an amylase complex from germinating barley and named it "diastase".[16][17] It is from this term that all subsequent enzyme names tend to end in the suffix -ase.
In 1862, Russian biochemist Aleksandr Yakovlevich Danilevsky (1838–1923) separated pancreatic amylase from trypsin.[18][19]
Evolution
Salivary amylase
Following the
Despite the obvious benefits, early humans did not possess salivary amylase, a trend that is also seen in evolutionary relatives of the human, such as chimpanzees and bonobos, who possess either one or no copies of the gene responsible for producing salivary amylase.[21]
Like in other mammals, the pancreatic alpha-amylase AMY2 was duplicated multiple times. One event allowed it to evolve salivary specificity, leading to the production of amylase in the saliva (named in humans as AMY1). The 1p21.1 region of human chromosome 1 contains many copies of these genes, variously named AMY1A, AMY1B, AMY1C, AMY2A, AMY2B, and so on.[22]
However, not all humans possess the same number of copies of the AMY1 gene. Populations known to rely more on saccharides have a higher number of AMY1 copies than human populations that, by comparison, consume little starch. The number of AMY1 gene copies in humans can range from six copies in agricultural groups such as European-American and Japanese (two high starch populations) to only two to three copies in hunter-gatherer societies such as the
The correlation that exists between starch consumption and number of AMY1 copies specific to population suggest that more AMY1 copies in high starch populations has been selected for by natural selection and considered the favorable phenotype for those individuals. Therefore, it is most likely that the benefit of an individual possessing more copies of AMY1 in a high starch population increases fitness and produces healthier, fitter offspring.[22]
This fact is especially apparent when comparing geographically close populations with different eating habits that possess a different number of copies of the AMY1 gene. Such is the case for some Asian populations that have been shown to possess few AMY1 copies relative to some agricultural populations in Asia. This offers strong evidence that natural selection has acted on this gene as opposed to the possibility that the gene has spread through genetic drift.[22]
Variations of amylase copy number in dogs mirrors that of human populations, suggesting they acquired the extra copies as they followed humans around.[23] Unlike humans whose amylase levels depend on starch content in diet, wild animals eating a broad range of foods tend to have more copies of amylase. This may have to do with mainly detection of starch as opposed to digestion.[20]
References
- PMID 15299664.
- S2CID 45819617.
- ^ "Effects of pH (Introduction to Enzymes)". worthington-biochem.com. Retrieved 17 May 2015.
- ^ "Amylase, Alpha, I.U.B.: 3.2.1.11,4-α-D-Glucan glucanohydrolase".
- ^ Wadler J (8 September 2009). "Chew It Up, Spit It Out, Then Brew. Cheers!". New York Times. Retrieved 27 March 2013.
- ISBN 0-13-981176-1.
- PMID 8227545.
- S2CID 23522631.
- ^ "Sollpura". Anthera Pharmaceuticals. Archived from the original on 18 July 2015. Retrieved 21 July 2015.
- PMID 15005645. Archived from the original(PDF) on 2011-07-28.
- PMID 11303086.
- ^ "Acute Pancreatitis – Gastrointestinal Disorders". Merck Manuals Professional Edition. Merck.[permanent dead link]
- ^ "First Biomarker for Human Sleepiness Identified". Record. Washington University in St. Louis. 25 January 2007.
- ^
- Leuchs EF (1831). "Wirkung des Speichels auf Stärke" [Effect of saliva on starch]. Poggendorff's Annalen der Physik und Chemie. 22 (8): 623. . (Modern citation: Annalen der Physik 98 (8): 623.)
- Leuchs EF (1831). "Über die Verzuckerung des Stärkmehls durch Speichel" [On the saccharification of powdered starch by saliva]. Archiv für die gesammte Naturlehre. 21: 105–107.
- ^ "History of Biology: Cuvier, Schwann and Schleiden". pasteur.fr. 8 April 2002. Archived from the original on 24 September 2015. Retrieved 17 May 2015.
- ^ Payen A, Persoz JF (1833). "Mémoire sur la diastase, les principaux produits de ses réactions et leurs applications aux arts industriels" [Memoir on diastase, the principal products of its reactions and their applications to the industrial arts]. Annales de chimie et de physique. 2nd series. 53: 73–92.
- ^ "Industrial Enzymes for Food Production". Archived from the original on 5 December 2008.
- ^ Danilewsky AJ (1862). "Über specifisch wirkende Körper des natürlichen und künstlichen pancreatischen Saftes" [On the specifically-acting principles of natural and artificial pancreatic fluid]. Virchows Archiv für Pathologische Anatomie und Physiologie und für Klinische Medizin. 25: 279–307. Abstract (in English).
- ^ "A History of Fermentation and Enzymes". navi.net. Archived from the original on 2022-01-10. Retrieved 2008-10-25.
- ^ PMID 31084707.
- doi:10.1511/2010.83.140. Archived from the originalon 2016-03-04. Retrieved 2015-08-15.
- ^ PMID 17828263.
- PMID 27406651.
