July 20, 2024

Understanding Trypsin – The Protease Enzyme Involved in Protein Digestion

Trypsin is a serine protease enzyme that is produced in the pancreas as the inactive proenzyme trypsinogen. Trypsinogen is activated when it reaches the small intestine during protein digestion by another pancreatic enzyme called enterokinase. Once activated,it acts as the primary protease in small intestine and plays a key role in breaking down dietary proteins into smaller peptide chains and amino acids.

Structure and Mechanism of Action

Structurally, Trypsin composed of a single polypeptide chain that folds into two beta-barrel domains connected by a linker region. It contains a catalytic triad made up of three amino acids – histidine, aspartic acid and serine. These amino acids work together to hydrolyze the peptide bonds of proteins through a process called hydrolysis. Specifically, the serine amino acid performs a nucleophilic attack on the carbonyl carbon of the peptide bond, causing it to break and release the amino acids. This process continues down the protein chains, reducing proteins into smaller and smaller fragments.


As a digestive protease, it preferentially cleaves peptide chains at the carboxyl side of the amino acids lysine or arginine. However, it can also hydrolyze other peptide bonds to a lesser extent. Some of the preferred protein substrates include:

Caseins: The main proteins found in milk which are efficiently broken down by trypsin.

Collagen: The structural protein in connective tissues which provides strength and flexibility.

– Soy proteins: Found abundantly in soy and soy products. It helps liberate amino acids from soy.

Fibrinogen: A glycoprotein involved in blood clotting which it degrades.

Bacterial cell walls: It helps digest bacterial cell walls during protein breakdown.

Regulation of Trypsin Activity

To prevent damage to the intestinal walls,  its activity needs to be tightly regulated. This is achieved through several mechanisms:

Trypsinogen auto-activation: Initial activation of Trypsin to it  is a controlled step involving enterokinase.

Pancreatic secretory inhibitor (PSTI): PSTI is co-secreted by pancreas to neutralize any trypsin that escapes into pancreatic secretions.

– Tissue factor pathways inhibitor (TFPI):
TFPI present in intestinal mucosa scavenges trypsin to prevent damage.

– Enterokinase inhibition: Drugs like camostat mesilate block enterokinase to suppress it production.

Physiological Role

As the primary protease of small intestine, it plays a key role in

– Protein digestion: It efficiently breaks down ingested proteins into amino acids required for protein synthesis and growth in the body.

– Absorption of amino acids: The smaller products of it action like di- and tri-peptides can be absorbed into bloodstream from small intestine.

Intestinal health: it maintains gut barrier function and protects against infection by degrading bacterial cell walls.

Trypsin is a critical digestive enzyme produced by the pancreas that efficiently breaks down dietary proteins into absorbable smaller units through its catalytic activity, thus supporting overall health, growth and protein metabolism in the body.

1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it