Difference Between Endopeptidase and Exopeptidase

The key difference between endopeptidase and exopeptidase is that the endopeptidase breaks peptide bonds within the protein molecules while the exopeptidase cleaves peptide bonds at the terminals of the protein molecules.

Proteins are important macromolecules, which are essential for most of the biochemical reactions occurring in all organisms. Different amino acids join together and form these proteins. Furthermore, enzymes catalyze the hydrolysis of proteins back into amino acids. They are specific enzymes called proteases or peptidases. Therefore, they have the capability to break down peptide chains of proteins into amino acids. Moreover, peptidases can be endopeptidases or exopeptidases.

CONTENTS

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

What is Endopeptidase?

Endopeptidase is a type of protein-cleaving enzyme that breaks peptide bonds within the protein molecule. As a result of the endopeptidase reaction, proteins split into peptide chains.

Moreover, peptide chains are sequences of amino acids. Therefore, single amino acids do not result due to the action of endopeptidase. In other words, endopeptidases cannot separate monomers of proteins. Pepsin, Chymotrypsin, Thermolysin and Trypsin are examples for endopeptidases.

What is Exopeptidase?

Exopeptidases are the enzymes that catalyze the breaking of peptide bonds at the terminals and removing single amino acids from the protein molecules.

Furthermore, carboxypeptidase and aminopeptidase are two types of exopeptidases. Dipeptidase is another name uses to refer exopeptidase.

What are the Similarities Between Endopeptidase and Exopeptidase?

• Both are enzymes.
• They are proteins.
• Endopeptidase and Exopeptidase catalyze the hydrolysis of proteins. Hence, they are proteases.
• They are secreted by the stomach, pancreas and intestinal cells.
• Both types are important in protein digestion in our body.

What is the Difference Between Endopeptidase and Exopeptidase?

Peptidases break peptide bonds in proteins. Endopeptidase and exopeptidase are two types among different types of peptidases. Endopeptidases break peptide bonds within the molecule while exopeptidases break peptide bonds at the terminals. Threfore, peptide chains will result due to the action of endopeptidases while monomers will result due to the action of exopeptidases. Enterokinase and enteropeptidase are synonyms of endopeptidases  while dipeptidase is a synonym for exopeptidase. The following infographic prensents the difference between endopeptidase and exopeptidase as a side by side comparison.

Summary – Endopeptidase vs Exopeptidase

Endopeptidase and exopeptidase are two types of peptidase enzymes. They cleave peptide bonds in protein molecules. These enzymes help to digest proteins in your diet. Stomach, pancreas and intestinal cells release these peptidases in order to maximize protein degradation and nutrient absorption. Endopeptidase cleaves peptide bonds within the protein molecules and results in peptide chains, not the monomers. Exopeptidase cleaves peptide bonds at the terminals and results in single amino acids. This is the difference between endopeptidase and exopeptidase.

Reference:

1.“Endopeptidase.” 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.”Mechanism chymotrypsin part 2″By Yikrazuul – Own work, (CC BY-SA 3.0) via Commons Wikimedia  
2.”Carboxypeptidase A”By Lijealso (Public Domain) via Commons Wikimedia