Question 8
Describe the digestive role of chymotrypsin. What two other digestive enzymes of the same category are secreted by its source gland?
The enzyme trypsin (present in the pancreatic juice) activates the inactive enzyme chymotrypsinogen into chymotrypsin.
Chymotrypsinogen 
Chymotrypsin
(Inactive) (Active)
The activated chymotrypsin plays an important role in the further breakdown of the partially-hydrolysed proteins.
Proteins
Peptides
The other digestive enzymes of the same category are trypsinogen and carboxypeptidase. These are secreted by the same source-gland, pancreas.
Trypsinogen is present in an inactive form in the pancreatic juice. The enzyme enterokinase – secreted by the intestinal mucosa – activates trypsinogen into trypsin.
Trypsinogen
Trypsin + Inactive peptide
The activated trypsin then further activates the remaining trypsinogen and activates other pancreatic enzymes such as chymotrypsinogen and carboxypeptidase. Trypsin also helps in breaking down proteins into peptides.
Proteins
Peptides
Carboxypeptidases act on the carboxyl end of the peptide chain and help in releasing the last amino acids.
Peptides
Small peptide chain + Amino acids
