Pepsin

Definition

Pepsin is a digestive enzyme primarily responsible for breaking down proteins in the stomach. It is activated from its precursor, pepsinogen, by the acidic environment of the stomach.

5 Must Know Facts For Your Next Test

1. Pepsin is most active at a pH of 1.5 to 2.0, which is highly acidic.
2. It is secreted by the chief cells in the stomach lining as pepsinogen.
3. Pepsin plays a crucial role in protein digestion by cleaving peptide bonds.
4. Hyperacidity can increase pepsin activity and contribute to gastric ulcers.
5. Antacids, histamine blockers, and proton-pump inhibitors can reduce pepsin activity by increasing stomach pH.

Review Questions

• What type of macromolecule does pepsin primarily break down?
• How is pepsinogen converted into its active form, pepsin?
• Name two types of medications that can decrease pepsin activity.

Related terms

Pepsinogen:

The inactive precursor of pepsin, secreted by chief cells in the stomach.

Hydrochloric Acid (HCl): A strong acid produced in the stomach that activates pepsinogen into pepsin.

Proton-Pump Inhibitors (PPIs): Medications that reduce stomach acid production, thereby decreasing pepsin activity.