Definition
An amylase is an enzyme that breaks starch down into sugar. Amylase is present in human saliva, where it begins the chemical process of digestion and in the pancreas also makes amylase in order to convert starch into glucose to supply the body with energy.
Basics
An amylase is an enzyme that breaks starch down into sugar. Amylase is present in human saliva, where it begins the chemical process of digestion. Foods that contain much starch but little sugar, such as rice and potato, taste slightly sweet as they are chewed because amylase turns some of their starch into sugar in the mouth. The pancreas also makes amylase (alpha amylase) to hydrolyse dietary starch into di- and trisaccharides which are converted by other enzymes to glucose to supply the body with energy. Plants and some bacteria also produce amylase. As diastase, amylase was the first enzyme to be discovered and isolated (by Anselme Payen in 1833). Specific amylase proteins are designated by different Greek letters. All amylases are glycoside hydrolases and act on α-1,4-glycosidic bonds. It will start to denature at around 60C.
α-Amylase is an enzyme that hydrolyses alpha-bonds of large alpha-linked polysaccharides such as starch and glycogen, yielding glucose and maltose. It is the major form of amylase found in humans and other mammals. It is also present in seeds containing starch as a food reserve, and is secreted by many fungi.
Other forms of amylases are β-Amylase and γ-Amylase.
Uses: Amylase enzymes finds use in bread making and to break down complex sugars such as starch (found in flour) into simple sugars. Yeast then feeds on these simple sugars and converts it into the waste products of alcohol and CO2. This imparts flavour and causes the bread to rise. While Amylase enzymes are found naturally in yeast cells, it takes time for the yeast to produce enough of these enzymes to break down significant quantities of starch in the bread. This is the reason for long fermented doughs such as sour dough. Modern bread making techniques have included amylase enzymes (often in the form of malted barley) into bread improver thereby making the bread making process faster and more practical for commercial use.
When used as a food additive Amylase has E number E1100, and may be derived from swine pancreas or mould mushroom.
Bacilliary amylase is also used in clothing and dishwasher detergents to dissolve starches from fabrics and dishes.
An inhibitor of alpha-amylase called phaseolamin has been tested as a potential diet aid.
Blood serum amylase may be measured for purposes of medical diagnosis. A normal concentration is in the range 21-101 U/L. A higher than normal concentration may reflect one of several medical conditions, including acute inflammation of the pancreas, macroamylasemia, perforated peptic ulcer, and mumps. Amylase may be measured in other body fluids, including urine and peritoneal fluid
Hazards: Workers in factories that work with amylase for any of the above uses are at increased risk of occupational asthma. 5-9% of bakers have a positive skin test, and a fourth to a third of bakers with breathing problems are hypersensitive to amylase.
History In 1831 Erhard Friedrich Leuchs (1800-1837) described the diastatic action of salivary ptyalin (amylase) on starch. The modern history of enzymes began in 1833 when French chemists described the isolation of an amylase complex from germinating barley and named it diastase. In 1862 Danielewski separated pancreatic amylase from trypsin.
The digestive functions of saliva include moistening food and helping to create a food bolus, so it can be swallowed easily. Saliva contains the enzyme amylase that breaks some cooked starch down into sugar. Thus, digestion of food begins in the mouth. Salivary glands also secrete salivary lipase (a more potent form of lipase) to start fat digestion. Lipase has great role in fat digestion in new-born as their pancreatic lipase will develop later. It also has a protective function for the teeth to prevent bacteria build-up and to help wash away food particles.
Source: Wikipedia (All text is available under the terms of the GNU Free Documentation License and Creative Commons Attribution-ShareAlike License.)
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