Pepsin

Definition

Pepsin is an enzyme produced in the stomach that breaks down proteins into smaller peptides during digestion. It is activated from its inactive form, pepsinogen, in the presence of stomach acid (hydrochloric acid).

Related terms

Proteins:

Large biomolecules composed of one or more long chains of amino acid residues essential for the structure, function, and regulation of the body's cells, tissues, and organs.

Amino acids: Organic compounds that combine to form proteins; amino acids and proteins are the building blocks of life.

Hydrochloric acid: A strong corrosive acid present in gastric juice that activates digestive enzymes such as pepsinogen into pepsin and helps break down foods in the stomach