amylase

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amylase (ăm´əlās´), enzyme having physiological, commercial, and historical significance, also called diastase. It is found in both plants and animals. Amylase was purified (1835) from malt by Anselme Payen and Jean Persoz. Their work led them to suspect that similar substances, now known as enzymes, might be involved in biochemical processes. Amylase hydrolyzes starch, glycogen, and dextrin to form in all three instances glucose, maltose, and the limit-dextrins. Salivary amylase is known as ptyalin; although humans have this enzyme in their saliva, some mammals, such as horses, dogs, and cats, do not. Ptyalin begins polysaccharide digestion in the mouth; the process is completed in the small intestine by the pancreatic amylase, sometimes called amylopsin. The amylase of malt digests barley starch to the disaccharides that are attacked by yeast in the fermentation process.

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amylase A member of a group of enzymes that hydrolyse (see HYDROLYSIS) starch or glycogen by the splitting of glucosidic bonds (see GLUCOSIDE), so giving rise to the sugars glucose, dextrin, or maltose. They are widely distributed in plants and animals, but occur particularly richly in germinating seeds e.g. those of barley, peas, and maize) in which the amylase mobilizes food reserves for the growth of the seedling.

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amylase Any of a group of closely related enzymes that degrade starch, glycogen, and other polysaccharides. Plants contain both α- and β-amylases; the name diastase is given to the component of malt containing β-amylase, important in the brewing industry. Animals possess only α-amylases, found in pancreatic juice (as pancreatic amylase) and also (in humans and some other species) in saliva (as salivary amylase or ptyalin). Amylases cleave the glycosidic bonds of the long polysaccharide chains, producing a mixture of glucose and maltose.

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amylase Digestive enzyme secreted by the salivary glands (salivary amylase) and the pancreas (pancreatic amylase. It aids digestion by breaking down starch into maltose (a disaccharide) and then glucose (a monosaccharide).

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amylase A member of a group of enzymes that hydrolyse starch or glycogen by the splitting of glycosidic bonds, so giving rise to the sugars glucose, dextrin, or maltose. Amylases are widely distributed in plants and animals, occurring in microorganisms and, for example, in pancreatic juices and salivary glands.

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am·yl·ase / ˈaməˌlās; -ˌlāz/ • n. Biochem. an enzyme, found chiefly in saliva and pancreatic fluid, that converts starch and glycogen into simple sugars.

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amylase (am-i-layz) n. an enzyme that occurs in saliva and pancreatic juice and aids the digestion of starch, which it breaks down into glucose, maltose, and dextrins.