Editing Diastase

{{Short description|Class of enzymes}}
A '''diastase''' ({{IPAc-en|ˈ|d|aɪ|ə|s|t|eɪ|z}}; from [[Greek language|Greek]] διάστασις, "separation") is any one of a group of [[enzyme]]s that [[catalysis|catalyses]] the breakdown of [[starch]] into [[maltose]]. For example, the diastase [[α-Amylase|α-amylase]] degrades starch to a mixture of the disaccharide maltose; the trisaccharide maltotriose, which contains three α (1-4)-linked glucose residues; and oligosaccharides, known as dextrins, that contain the α (1-6)-linked glucose branches.<ref>{{Cite journal| doi=10.1056/NEJM197506052922308| 
author=Gray, G.M.
| title=Carbohydrate digestion and absorption
| journal=New England Journal of Medicine
| year=1975
| volume=292| issue=23
| pages=1225–1230| pmid=1093023}}</ref>

Diastase was the first enzyme discovered.<ref>See:
*  {{cite book|first1=Robert |last1=Hill |first2=Joseph |last2=Needham 
|title=The Chemistry of Life: Eight Lectures on the History of Biochemistry |location=London |publisher=Cambridge University Press 
|year=1970 |page=17 
|isbn=9780521073790 |url=https://books.google.com/books?id=IvM8AAAAIAAJ&pg=PA17}}
*  {{cite book |first=Richard B. |last=Silverman |title=The Organic Chemistry of Enzyme-catalyzed Reactions |edition=2nd |location=London 
|publisher=Academic Press |year=2002 |page=1 
|isbn=9780126437317 |url=https://books.google.com/books?id=Wj9EufQ2XEQC&pg=PA1}}
*  {{cite book |first=Jochanan |last=Stenesh |title=Biochemistry 
|volume=2 |location=New York |publisher=Plenum |year=1998 |page=83 
|isbn=9780306457333 |url=https://books.google.com/books?id=lp7sAL5oqFcC&pg=PA83}}
*  {{cite book |editor1-first=Robert A. |editor1-last=Meyers |title= Molecular Biology and Biotechnology: A Comprehensive Desk Reference 
|location=New York |publisher=Wiley-VCH |year=1995 |page=296 
|isbn=9780471186342 |url=https://books.google.com/books?id=2TjAqddKsscC&pg=PA296}}</ref> It was extracted from [[malt]] solution in 1833 by [[Anselme Payen]] and [[Jean-François Persoz]], chemists at a French sugar factory.<ref>Payen & Persoz (1833), page 77.  Payen and 
Persoz found diastase in the seeds of barley, oats, and wheat, as well as in potatoes (Payen & Persoz (1833), page 76).</ref> The 
name "diastase" comes from the Greek word διάστασις (''diastasis'') (a parting, a separation), because when beer [[mashing|mash]] is heated, the enzyme causes the starch in the barley seed to transform quickly into soluble sugars and hence the husk to separate from the rest of the seed.<ref>Payen & Persoz (1833), pages 75-76.</ref><ref>{{usurped|1=[https://web.archive.org/web/20110714142902/http://www.myetymology.com/english/diastase.html Etymology of "diastase"]}}</ref> Today, "diastase" refers to any α-, β-, or γ-[[amylase]] (all of which are [[hydrolase]]s) that can break down [[carbohydrate]]s.<ref>{{cite book |last=Oliver |first=Garrett 
|title=The Oxford Companion to Beer |publisher=Oxford University Press 
|location=Oxford |year=2011 |isbn=978-0199912100 |page=49 
|url=https://books.google.com/books?id=oWQdjnVo2B0C&pg=PA49
|quote=Most of the activity of diastase can be attributed to the activities of two enzymes, alpha and beta amylase, and, to a lesser extent, gamma amylase (together, the amylases), although many other enzymes are also present. |access-date=2013-12-27}}</ref>

The commonly used [[-ase]] suffix for naming enzymes was derived from the name diastase.<ref>The naming of enzymes using the suffix "-ase" has been traced to French scientist [[Émile Duclaux]] (1840-1904), who intended to honor the discoverers of diastase by 
introducing the practice in his book [https://archive.org/details/traitdemicrobi02ducl/page/9  ''Traité de Microbiologie''], vol. 2 (Paris, France:  Masson and Co., 1899), Chapter 1, especially page 9.</ref>

When used as a [[pharmaceutical drug]], diastase has the [[ATC code]] {{ATC|A09|AA01}}.

Amylases can also be extracted from other sources including plants, saliva and milk.

==Clinical significance==
Urine diastase is useful in diagnosing uncertain abdominal cases (especially when [[pancreatitis]] is suspected), stones in the [[common bile duct]] ([[choledocholithiasis]]), [[jaundice]] and in ruling out post-operative injury to the pancreas; provided that the diastase level is correlated with clinical features of the patient.<ref>{{cite journal|last1=Foged|first1=Jens|title=The diagnostic value of urine diastase|journal=The American Journal of Surgery|date=March 1935|volume=27|issue=3|pages=439–446|doi=10.1016/S0002-9610(35)91022-4}}</ref>

Diastase is also used in conjunction with [[periodic acid–Schiff stain]] in histology. For example, glycogen is darkly stained by PAS but can be dissolved by diastase. Fungi, on the other hand, stain darkly with PAS even after treatment by diastase.

==See also==
* [[Takadiastase]]
* [[Whipple disease]]
* [[Amylase]]

==References==
{{Reflist}}
* Payen, A. et J.-F. Persoz (1833) [https://books.google.com/books?id=Q9I3AAAAMAAJ&pg=PA73  "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.

==External links==
* {{MeshName|Diastase}}
* [http://www.websparrow.org/pharmacy/introduction-and-uses-of-diastase-enzyme Introduction and Uses of Diastase Enzyme]

{{Digestives}}

[[Category:Carbohydrate metabolism]]
[[Category:Hydrolases]]