What are the enzymes of the digestive system?

The stomach breaks down food through a combination of mechanical and chemical processes.

Mechanical processes

  • Chewing: The first step in breaking down food is chewing. Chewing breaks food into smaller pieces, which makes it easier to swallow and digest.
  • Peristalsis: Peristalsis is the rhythmic contractions of the muscles in the esophagus and stomach. These contractions help to move food through the digestive system.


mechanical digestion

Chemical processes

  • Gastric juices: The stomach produces gastric juices, which contain hydrochloric acid and pepsin. Hydrochloric acid creates an acidic environment that kills bacteria and activates pepsin. Pepsin is an enzyme that breaks down proteins into smaller peptides.
  • Bile: Bile is produced by the liver and stored in the gallbladder. Bile helps to break down fats into smaller molecules.
  • Pancreatic juices: The pancreas produces pancreatic juices, which contain enzymes that break down carbohydrates, proteins, and fats.



The following enzymes are involved in the stomach:

  • Pepsin: Breaks down proteins into smaller peptides
  • Gastric lipase: Breaks down some dietary fats
  • Hydrochloric acid: Creates an acidic environment that kills bacteria and activates pepsin
  • Gelatinase: Breaks down collagen, a protein found in connective tissue
  • Rennin: Coagulates milk proteins in infants