The α-amylase occur in saliva, pancreatic juice, malt, and certain bacteria. α-amylase is the major form of amylase found in human, most prominently in pancreatic juice and saliva. Each of which has its own isoform of human α-amylase. They behave differently on isoelectric focusing, and can also be separated in testing by using specific monoclonal antibodies.
α-amylase catalyzes the first step in the digestion of starch, a main source of carbohydrate in the human diet. Amylase present in human saliva was one of the first enzymes ever to be recognized.
Salivary amylase has a relatively short active contact time with starch. Once a food bolus is swallowed and infiltrated with gastric juice, its catabolic activity is mostly stopped by low acidic pH. Some activity remains within particles due to the barrier protection provided by partially digested starch on the outside of the particle.
The salivary amylase is an amylolytic enzyme, which can acts on cooked or boiled starch and converts it in to maltose. The main function of salivary alpha-amylase is the enzymatic digestion of starch into maltose and dextrin. This form of amylase is also called "ptyalin". Ptyalin acts on linear α (1, 4) glycosidic linkages and, it will break large, insoluble starch molecules into soluble starches (amylodextrin, erythrodextrin, and achrodextrin) producing successively smaller starches and ultimately maltose. Salivary amylase is inactivated in the stomach by gastric acid.
Enzyme α-amylase
