Amylase is an enzyme responsible for breaking down starch into sugar . It is highly present in the human saliva , where it helps digestion by breaking down food into simpler substances. Food items which contain greater amount of starch and less sugar, namely rice and potato , taste sweet when chewed because amylase action breaks down some amount of starch into sugar in the mouth itself. The Pancreas is also known to form alpha amylase in order to hydrolyse dietary starch into disaccharides and trisaccharides. These are then converted by other enzymes into glucose which then gives energy to the body. Some plants and bacteria also known to support the production of amylase. All amylases are glycoside hydrolases and are made up of α-1,4-glycosidic linkages.

Classification and Benefits

There are three major kinds of amylases.

α-Amylase

It is known under the chemical name, 1,4-α- D -glucan glucanohydrolase or glycogenase. The α-amylases are particularly calcium metalloenzymes and are not able to function without calcium. They act at different locations on the starch chain where they aid in breaking down long-chains of carbohydrates , ultimately forming maltotriose and maltose from amylose as well as glucose and limit dextrin from amylopectin . α-amylases can act anywhere on the substrate , and therefore tend to be faster-acting than any other amylase enzyme.

β-Amylase

β-amylase is known under the alternate name, 1,4-α- D -glucan maltohydrolase or glycogenase and saccharogen amylase. β-amylase is another form of amylase, largely synthesized by bacteria , fungi and some plants . It works from the non reducing end and helps in catalyzing the hydrolysis of the second α-1,4 glycosidic bond, cleaving off two glucose units at the same time.

γ-Amylase

Called under the alternative name, Glucan 1,4-α-glucosidase, amyloglucosidase, exo-1,4-α-glucosidase, glucoamylase, lysosomal α-glucosidase, it is also referred to as 1,4-α- D -glucan glucohydrolase. It mainly cleaves the last α(1-4)glycosidic linkage at the non reducing end of amylose and amylopectin , forming glucose . It also cleaves α(1-6) glycosidic linkages.

Uses

Amylase enzyme finds varied use in bread making where it helps in the breaking down of complex sugars like starch into simpler sugars. Once the dough is prepared, the yeast feeds on these simple sugars and converts them into waste products of alcohol and carbon-dioxide. It is this process that gives flavor to the bread and causes it to rise. Amylase enzymes are found naturally in yeast cells. The yeast takes great amount of time to produce enzymes which break down significant quantities of starch in the bread into smaller substances.

References

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