Ptyalin – What is Ptyalin, Action of Ptyalin


is a form of amylase found in saliva of humans and some animals. Another name of ptylin is salivary amylase. It is weak enzyme but the most important amylolytic enzyme secreted in mouth (buccal cavity) by the salivary glands. This type of amylase is found only in humans.

Action of Ptyalin:

The main function of ptyalin is to catalyze the hydrolysis of starch into maltose and dextrin. Following are the steps in the process of digestion of carbohydrate in buccal cavity, showing the action of Ptyalin:

  1. Boiled starch + Ptyalin = Soluble starch
  2. Soluble starch + Ptyalin = Erythrodextrin + Maltose
  3. Erythrodextrin + Maltose + Ptyalin = Acrodextrin + Maltose
  4. Acrodextrin + Maltose + Ptyalin = Isomaltose + Maltose

This action of Ptyalin also occurs in the stomach before the concentration of Hcl becomes adequate.

From the above explanation, it is clear that Ptyalin initiates the digestion of carbohydrates in a favourable way beginning from buccal cavity. Due to absence of lipolytic and proteolytic enzyme in saliva, fat and protein digestion do not occur in the buccal cavity.

Process of Digestion

Digestion is the process of breaking down of food into smaller components, both chemically and mechanically. Human digestive system there are three main components:

  • Buccal cavity
  • Stomach
  • Small intestine

Mainly three types of foods are digested in human digestive tract:

  • Carbohydrates
  • Proteins
  • Fats

Several enzymes act on the food ingested. All the vitalities of food are absorbed by the body. The digested food is the source of energy to sustain the body. Left over stuff is eliminated from the body in form of feces.

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