Pepsin vs. Pepsinogen — What's the Difference?
Edited by Tayyaba Rehman — By Fiza Rafique — Updated on September 22, 2023
Pepsin is an active enzyme that breaks down proteins in the stomach, while pepsinogen is its inactive precursor produced by stomach cells. Activation of pepsinogen to pepsin occurs in the acidic environment of the stomach.
Difference Between Pepsin and Pepsinogen
Table of Contents
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Key Differences
Pepsin is an enzyme that functions in the stomach to break down proteins into smaller peptides. Pepsinogen, on the other hand, is an inactive form of pepsin that is initially secreted by the stomach lining.
The production of pepsinogen by chief cells in the stomach is the first step toward protein digestion. Pepsinogen gets converted into pepsin when it encounters the acidic environment of the stomach.
Pepsin is active only under acidic conditions, usually with a pH of 1.5 to 2. Pepsinogen is stable under neutral conditions and becomes pepsin when the pH drops below 5.
Pepsin plays an essential role in digestion by hydrolyzing peptide bonds in proteins, making them easier to absorb. Pepsinogen is vital because its inactive form prevents the enzyme from digesting the very cells that produce it.
Both pepsin and pepsinogen are crucial for the process of protein digestion, but their functions and activation mechanisms are distinctly different. While pepsin acts as the worker, pepsinogen serves as a safeguard to ensure that digestion occurs only where it should.
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Comparison Chart
Activity
Active enzyme
Inactive precursor
Function
Protein digestion
Becomes active enzyme
Stability
Acidic conditions
Neutral conditions
Produced By
Activation of pepsinogen
Chief cells in stomach
Role
Hydrolyzes proteins
Precautionary mechanism
Compare with Definitions
Pepsin
Active in acidic conditions.
Pepsin is most effective at a low pH.
Pepsinogen
Activated at low pH.
Pepsinogen turns into pepsin in acidic conditions.
Pepsin
Hydrolyzes peptide bonds.
Pepsin breaks down proteins into smaller peptides.
Pepsinogen
Produced by chief cells.
Pepsinogen is secreted by chief cells in the stomach lining.
Pepsin
Essential for protein digestion.
Without pepsin, protein digestion would be incomplete.
Pepsinogen
Stable in neutral conditions.
Pepsinogen does not degrade proteins until it's activated.
Pepsin
Derived from pepsinogen.
Pepsin is activated from pepsinogen in the stomach.
Pepsinogen
Inactive form of pepsin.
Pepsinogen is converted into pepsin in the stomach.
Pepsin
A stomach enzyme.
Pepsin helps digest the proteins in food.
Pepsinogen
A safeguard mechanism.
Pepsinogen ensures that stomach cells are not digested.
Pepsin
A digestive enzyme found in gastric juice that catalyzes the breakdown of protein to peptides.
Pepsinogen
The inactive precursor to pepsin, formed in cells of the mucous membrane of the stomach and converted to pepsin by autocatalysis in the presence of hydrochloric acid.
Pepsin
Pepsin is an endopeptidase that breaks down proteins into smaller peptides. It is produced in the gastric chief cells of the stomach lining and is one of the main digestive enzymes in the digestive systems of humans and many other animals, where it helps digest the proteins in food.
Pepsinogen
(biochemistry) A zymogen that is converted into pepsin by the hydrochloric acid in the stomach.
Pepsin
A substance containing pepsin, obtained from the stomachs of hogs and calves and used as a digestive aid.
Pepsinogen
A proenzyme, the antecedent of the enzyme pepsin. A substance contained in the form of granules in the peptic cells of the gastric glands. It is readily convertible into pepsin. Also called propepsin.
Pepsin
(enzyme) A digestive enzyme that chemically digests, or breaks down, proteins into shorter chains of amino acids.
Pepsinogen
Precursor of pepsin; stored in the stomach walls and converted to pepsin by hydrochloric acid in the stomach
Pepsin
A proteolytic enzyme (MW 34,500) contained in the secretory glands of the stomach. In the gastric juice it is united with dilute hydrochloric acid (0.2 per cent, approximately) and the two together constitute the active portion of the digestive fluid. It degrades proteins to proteoses and peptides, and is notable for having a very low pH optimum for its activity. It is the active agent in the gastric juice of all animals.
Pepsin
An enzyme produced in the stomach that splits proteins into peptones
Common Curiosities
How are pepsin and pepsinogen different?
Pepsin is active and breaks down proteins, while pepsinogen is inactive until activated.
What is pepsinogen?
Pepsinogen is the inactive precursor to pepsin.
Where is pepsin active?
In the acidic environment of the stomach.
Is pepsinogen always inactive?
Yes, until it encounters acidic conditions.
Why is pepsinogen important?
It serves as a safeguard, ensuring that pepsin doesn't digest stomach cells.
Is pepsin always active?
No, it is active only in acidic conditions.
What does pepsin break down?
Proteins into smaller peptides.
What is pepsin?
Pepsin is an active enzyme in the stomach that breaks down proteins.
Where is pepsinogen produced?
By chief cells in the stomach lining.
How is pepsinogen activated?
By the acidic conditions in the stomach.
Why is pepsin important?
It is essential for the digestion of proteins.
What activates pepsinogen?
Acidic conditions in the stomach.
Can pepsinogen work in an acidic environment?
It becomes active and turns into pepsin in acidic conditions.
Can pepsin work in a neutral environment?
No, it requires an acidic environment.
Is pepsin derived from pepsinogen?
Yes, pepsin is activated from pepsinogen.
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Fiza RafiqueFiza Rafique is a skilled content writer at AskDifference.com, where she meticulously refines and enhances written pieces. Drawing from her vast editorial expertise, Fiza ensures clarity, accuracy, and precision in every article. Passionate about language, she continually seeks to elevate the quality of content for readers worldwide.
Edited by
Tayyaba RehmanTayyaba Rehman is a distinguished writer, currently serving as a primary contributor to askdifference.com. As a researcher in semantics and etymology, Tayyaba's passion for the complexity of languages and their distinctions has found a perfect home on the platform. Tayyaba delves into the intricacies of language, distinguishing between commonly confused words and phrases, thereby providing clarity for readers worldwide.
