Difference Between Pepsin and Protease

The key difference between Pepsin and Protease is that the pepsin is one type of protease while the protease is an enzyme that cleaves protein into amino acids.

Proteins are important macromolecules made from different amino acids. Amino acids are the building blocks of proteins, and they polymerize into proteins by amide bonds. Some enzymes can break proteins into amino acids, and they are known as proteases. There are different types of proteases that differ according to the mechanism of hydrolysis. Among them, pepsin, which is a gastric protease is one such type.

 CONTENTS

1. Overview and Key Difference
2. What is Pepsin
3. What is Protease
4. Similarities Between Pepsin and Protease
5. Side by Side Comparison – Pepsin vs Protease in Tabular Form
6. Summary

What is Pepsin?

Pepsin is an efficient protease enzyme. It hydrolyzes peptide bonds between hydrophorbic and aromatic amino acids such as phenylalanine, tryptophan, and tyrosine, etc.

Pepsin has a catalytic aspartic group in its active site. Therefore, it is a gastric protease. Pepsinogen is the inactive form of pepsin. Stomach HCl converts pepsinogen into active pepsin. Under the acidic environment, pepsin cleaves protein compounds into amino acids. Moreover, high alkaline conditions and certain inhibitors can block the pepsin enzyme successfully.

What is Protease?

Protease is a general term that uses to refer the enzymes that cleave proteins. There are different types of proteases that differ based on the mechanism they use to break proteins into amino acids. Among them, trypsin, pepsin and chymotrypsin are the three main types. The stomach produces pepsins while secretes trypsin and chymotrypsin. These enzymes facilitate the breakdown of the protein component of your diet and enhance the nutrient absorption.

Proteases are also known as peptidases, and they can be endopeptidases or exopeptidases. Exopeptidases target cleave sites at the terminals of proteins while endopeptidases target sites within the proteins.

What are the Similarities Between Pepsin and Protease?

• Pepsin and protease are enzymes that break proteins.
• Both are enzymes.
• Both Pepsin and protease can break polymers into smaller units.

What is the Difference Between Pepsin and Protease?

Pepsin is a protease, which is the main gastric enzyme. Protease is a general term used to refer to protein-breaking enzymes including pepsin. There are several proteases. Among them, pepsin is an efficient protease that prefers to cleave hydrophobic and aromatic amino acids. The stomach secretes the pepsins, and they work under acidic conditions. The below infographic presents the difference between pepsin and protease in a tabular form.

Summary – Pepsin vs Protease

Amylase, protease and lipase are the three main types of enzymes that digest our foods into smaller units which can be absorbed readily into the bloodstream. Proteases are the enzymes which break proteins into amino acids. Amongst the several types of proteases, pepsin is one type. The stomach produces pepsin, and it prefers to cleave hydrophobic and aromatic amino acids. Pepsin serves as the main gastric enzyme.

Reference:

1.“Pepsin.” Egyptian Journal of Medical Human Genetics, Elsevier. Available here  
2.Britannica, The Editors of Encyclopaedia. “Proteolytic Enzyme.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 31 May 2018. Available here  

Image Courtesy:

1.’Pepsin’By Thiesi, (CC BY-SA 3.0) via Commons Wikimedia  
2.’HIV-1 protease 1GNO’By MZeg – Own work, (CC BY-SA 4.0) via Commons Wikimedia