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A List of Digestive Enzymes and Their Functions

List of Digestive Enzymes
Digestive enzymes play a key role in regulating and maintaining the functions of the digestive system properly. These enzymes not only helps in digestion but due to excess or lack of these enzymes, one can face difficulties in digestions too.
Saptakee Sengupta
Last Updated: Mar 19, 2018
Have you ever thought how food gets digested inside our body after we consume? The internal structure of our body is extremely potent in carrying out numerous functions, amongst which digestion is the most vital of all the processes taking place.

Our body's metabolism is controlled by a group of digestive enzymes, which are secreted by various organs of the digestive system. These enzymes aid in proper digestion of food. Enzymatic digestion begins in the mouth and extends to the intestine, where it gets converted to simpler particles and are then excreted by our body. These digestive enzymes act as catalysts for breakdown of carbohydrates, fats, and proteins.
The Source of Digestive Enzymes
Digestive enzymes help to breakdown polymeric macro-molecules into small building blocks, which are required by our body to maintain a healthy life. These enzymes are also present in the saliva, where they assist the first step of digestion. The enzymes are classified on the nature of substrates they work. Digestive enzymes are broadly classified into four groups. They are:

  • Proteolytic Enzyme: split proteins to amino acids
  • Lipolytic Enzyme: split fats to fatty acids and glycerol
  • Amylolytic Enzyme: split carbohydrate and starch to simple sugars
  • Nucleolytic Enzyme: split nucleic acids to nucleotides
The oral cavity or the mouth contains salivary glands. The salivary gland secretes the enzyme lysozyme which has an antibacterial action. The enzymes secreted by the mouth mainly provide protection against bacteria. Betaine helps to maintain a fluid balance inside the mouth.

Enzymes & Function:
Ptyalin- Converts starch to simple soluble sugars
Amylase- Converts starch to soluble sugars
Betaine- Maintains cell fluid balance as osmolytes
Bromelain- Anti-inflammatory agent, tenderizes meat
The enzymes released by the stomach are known as gastric enzymes. Stomach secretes hydrochloric acid which kills bacteria and germs and provides an acid environment for proper enzymatic activity of protease enzymes.

Enzymes & Function:
Pepsin- Breaks protein into small peptides
Gastric amylase- Degradation of starch
Gelatinase- Degradation of gelatin and collagen
Rennin- Conversion of liquid milk to solid particles
Gastric lipase- Degradation of butter fat
Pancreas is the main digestive gland of our body. The digestive enzymes of the pancreas breakdown carbohydrates and starch molecules to simple sugars. They also secrete a group of enzymes which help in degradation of nucleic acids. It functions both as an endocrine and exocrine gland.

Enzymes & Function:
Pancreatic lipase- Degrades triglycerides into fatty acids and glycerol
Phospholipase- Hydrolyzes phospholipids into fatty acids
Trypsin- Converts proteins to basic amino acids
Steapsin- Breakdown of triglycerides to glycerol and fatty acids
Chymotrypsin- Converts proteins to aromatic amino acids
Carboxypeptidase- Degradation of proteins to amino acids
Pancreatic amylase- Degradation of carbohydrates to simple sugars
Elastases- Degrade the protein elastin
Nucleases- Conversion of nucleic acids to nucleotides and nucleosides
Small Intestine
The final step of digestion is carried out by the small intestine. It contains a group of enzymes that breakdown the products undigested by the pancreas.The food gets converted to semi-solid form by the activity of the enzymes present in the duodenum, jejunum, and ileum.

Enzymes & Function:
Sucrase- Converts sucrose to disaccharides and monosaccharides
Maltase- Converts maltose to glucose
Lactase- Converts lactose to glucose and galactose
Isomaltase- Converts maltose to isomaltose
After knowing the types of digestive enzymes and their respective functions, I hope you understand how intricately the human digestive system works. The final product of digestion i.e. feces is then transported to the large intestine from where it is expelled.