Pepsin vs. Trypsin — What's the Difference?
By Urooj Arif & Fiza Rafique — Updated on April 15, 2024
Pepsin operates optimally in the acidic environment of the stomach, breaking down proteins, whereas trypsin functions in the small intestine's alkaline conditions, targeting peptide bonds.
Difference Between Pepsin and Trypsin
Table of Contents
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Key Differences
Pepsin is an enzyme that works in the acidic environment of the stomach to begin the digestion of proteins, breaking them down into smaller peptides. In contrast, trypsin operates in the alkaline environment of the small intestine, where it continues the process by targeting specific peptide bonds.
Both enzymes are crucial for protein digestion, but they activate at different stages of the digestive process and in different pH environments. Pepsin is secreted as pepsinogen, an inactive form that is activated by stomach acid. On the other hand, trypsin is secreted by the pancreas in its inactive form, trypsinogen, which is then activated in the small intestine.
This activation strategy protects the organs from the enzymes' digestive actions. Pepsin prefers to cleave at aromatic amino acids like phenylalanine and tryptophan, while trypsin targets the basic amino acids such as lysine and arginine. This specificity aids in effectively breaking down proteins into absorbable units.
While pepsin is crucial for initiating protein digestion under highly acidic conditions, trypsin's role is pivotal in finalizing digestion under neutral to basic conditions, ensuring proteins are fully broken down.
Comparison Chart
Optimal pH
Acidic (around pH 2)
Alkaline (around pH 8)
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Secretion Site
Stomach
Pancreas
Activation Form
Pepsinogen (in stomach)
Trypsinogen (in small intestine)
Substrate Specificity
Aromatic amino acids
Basic amino acids
Role in Digestive System
Initiates protein digestion
Finalizes protein digestion
Compare with Definitions
Pepsin
Pepsin becomes active in acidic conditions.
The acidic environment of the stomach activates pepsin to start protein breakdown.
Trypsin
Secreted by the pancreas into the small intestine.
The pancreas releases trypsinogen, which is activated to trypsin in the intestine.
Pepsin
Secreted by cells in the stomach lining.
Gastric cells release pepsinogen, which is converted to pepsin.
Trypsin
Trypsin targets specific peptide bonds in proteins.
Trypsin specifically cleaves at the peptide bonds next to lysine and arginine.
Pepsin
A digestive enzyme that breaks down proteins in the stomach.
Pepsin begins digesting the protein in your dinner as soon as it reaches the stomach.
Trypsin
An enzyme that aids in protein digestion in the small intestine.
Trypsin continues the breakdown of proteins as they enter the small intestine.
Pepsin
A primary enzyme in the stomach's digestive process.
Pepsin plays a key role in the stomach's ability to process proteins.
Trypsin
Trypsin is active in alkaline conditions.
The alkalinity of the small intestine activates trypsin for its role in digestion.
Pepsin
Pepsin cleaves proteins into smaller peptides.
Pepsin's action results in the formation of peptide fragments from larger proteins.
Trypsin
Finalizes the breakdown of proteins for absorption.
Trypsin ensures that protein digestion is complete before absorption.
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.
Trypsin
Trypsin (EC 3.4.21.4) is a serine protease from the PA clan superfamily, found in the digestive system of many vertebrates, where it hydrolyzes proteins. Trypsin is formed in the small intestine when its proenzyme form, the trypsinogen produced by the pancreas, is activated.
Pepsin
A digestive enzyme found in gastric juice that catalyzes the breakdown of protein to peptides.
Trypsin
A pancreatic enzyme that catalyzes the hydrolysis of proteins to form smaller polypeptide units.
Pepsin
A substance containing pepsin, obtained from the stomachs of hogs and calves and used as a digestive aid.
Trypsin
(enzyme) A digestive enzyme that cleaves peptide bonds (a serine protease)
Pepsin
(enzyme) A digestive enzyme that chemically digests, or breaks down, proteins into shorter chains of amino acids.
Trypsin
A proteolytic enzyme present in the pancreatic juice. Unlike the pepsin of the gastric juice, it acts in a neutral or alkaline fluid, and not only converts the albuminous matter of the food into soluble peptones, but also, in part, into leucin and tyrosin.
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.
Trypsin
An enzyme of pancreatic origin; catalyzes the hydrolysis of proteins to smaller polypeptide units
Pepsin
An enzyme produced in the stomach that splits proteins into peptones
Common Curiosities
How are pepsin and trypsin activated?
Pepsin is activated by stomach acid from pepsinogen, whereas trypsin is activated in the small intestine from trypsinogen.
Where does trypsin function in the body?
Trypsin functions in the small intestine to continue protein digestion.
What types of amino acids do pepsin and trypin target?
Pepsin targets aromatic amino acids, while trypsin targets basic amino acids.
What would happen if trypsin were activated in the pancreas?
Activation in the pancreas could lead to self-digestion and pancreatitis.
What is the primary function of pepsin?
Pepsin's primary function is to break down proteins into peptides in the stomach.
What pH levels are optimal for pepsin and trypsin?
Pepsin works best at a pH of about 2, highly acidic, while trypsin works best at a pH of about 8, which is alkaline.
Can pepsin function in the small intestine?
No, pepsin cannot function effectively in the small intestine due to the alkaline pH there.
What are the secretion sites of pepsin and trypsin?
Pepsin is secreted in the stomach, and trypsin is secreted by the pancreas into the small intestine.
What is the role of the pancreas in relation to trypsin?
The pancreas produces trypsinogen, which is transported to and activated in the small intestine.
What common conditions affect the functioning of pepsin and trypsin?
Conditions such as gastritis, pancreatitis, and other digestive disorders can impair their functioning.
How does the specificity of pepsin and trypsin aid digestion?
Their specificity allows for the efficient breakdown of proteins into absorbable peptides.
Are pepsin and trypsin necessary for protein absorption?
Yes, both enzymes are crucial for breaking proteins down to a size suitable for absorption.
How are pepsin and trypsin related to their respective secretion forms?
Pepsin is secreted as pepsinogen, and trypsin as trypsinogen, both inactive forms activated by their specific environments.
What are the health implications of malfunctioning pepsin or trypin?
Malfunction can lead to inadequate protein digestion, affecting overall health and nutrient absorption.
How does the body regulate the activity of pepsin and trypsin?
The body regulates these enzymes through their zymogen forms and the specific pH environments where they are activated.
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Written by
Urooj ArifUrooj is a skilled content writer at Ask Difference, known for her exceptional ability to simplify complex topics into engaging and informative content. With a passion for research and a flair for clear, concise writing, she consistently delivers articles that resonate with our diverse audience.
Co-written by
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.
