Diastase

Template:Short description A diastase (Template:IPAc-en; from Greek διάστασις, "separation") is any one of a group of enzymes that catalyses the breakdown of starch into maltose. For example, the diastase 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>Template:Cite journal</ref>

Diastase was the first enzyme discovered.<ref>See:

• Template:Cite book
• Template:Cite book
• Template:Cite book
• Template:Cite book</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 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>Template:Usurped</ref> Today, "diastase" refers to any α-, β-, or γ-amylase (all of which are hydrolases) that can break down carbohydrates.<ref>Template:Cite book</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 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 Template:ATC.

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>Template:Cite journal</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

• Payen, A. et J.-F. Persoz (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.

External links

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• Introduction and Uses of Diastase Enzyme