The protein-digesting enzyme secreted by the stomach wall in case of mammals is called

The correct answer is pepsin.

Key Points

Pepsin:

• Pepsin is a proteolytic enzyme that is produced by specialized cells in the stomach called chief cells.
• It is the powerful enzyme in gastric juice that digests proteins.
• Pepsin was one of the first enzymes discovered in 1836 by Theodor Schwann, a German physiologist.
• The Function Of Pepsin are:
  • It helps in digestion.
  • It breaks down the large polypeptides into smaller peptide fragments.
  • Help break down dietary proteins like eggs, meat, seeds, and other dairy products.

Important Points

Digestion in Stomach:

• The stomach stores the food for 4-5 hours. The food mixes thoroughly with the acidic gastric juice of the stomach by the churning movements of its muscular wall and is called the chyme.
• The proenzyme pepsinogen, on exposure to hydrochloric acid, gets converted into the active enzyme Pepsin, the proteolytic (breakdown of proteins or peptides into amino acids) enzyme of the stomach.
• Pepsin converts proteins into proteoses and peptones (peptides).
• The mucus and bicarbonates present in gastric juice play an important role in lubrication and protection of the mucosal epithelium from excoriation by highly concentrated hydrochloric acid.
  • HCl provides the acidic pH (pH 1.8) optimal for pepsins.
• Rennin is a proteolytic enzyme found in the gastric juice of infants which helps in the digestion of milk proteins.