Question

Trypsinogen is activated by
A. HCl
B. Enterokinase
C. Bile
D. Chymotrypsin

Answer 1

Hint: Trypsinogen is the precursor form of trypsin, which is a digestive enzyme. It is produced by the pancreas of the body and found in pancreatic juices which also include lipase, amylase and chymotrypsinogen. It is activated to trypsin by enteropeptidase which is found in the intestinal mucosa.

Complete answer:
Trypsinogen is a component of pancreatic juice which is composed of various digestive enzymes like chymotrypsinogen, elastase, pancreatic lipase, nucleases, carboxypeptidase, trypsinogen and amylase. These juices help in breakdown of the food into simpler form which can be absorbed by the cells of the body. Each enzyme has its own function as these are responsible for breakdown of various proteins, fats and carbohydrates.
Trypsinogen is a precursor form of trypsin which helps in breakdown of proteins into simple forms. It helps in breakdown of peptide bonds of basic amino acids so that the protein molecules can be digested. When the trypsin enzyme is inactive it is called trypsinogen and activated by another enzyme enteropeptidase which is also called enterokinase. Enterokinase is produced by the duodenum which is found in the intestinal mucosa. It helps in conversion of trypsinogen to trypsin. Trypsin also cleaves the peptide bond after lysine or an arginine, it can also cleave other trypsinogen which lead to an autocatalytic activation process.

Hence, the correct option is B. Enterokinase.

Note: Trypsin is stored in its inactivated form trypsinogen which helps it to only activate at the appropriate location. As if the trypsin is activated prematurely can be destructive and can lead to pancreatic self-digestion. Only 5% of the total trypsinogen gets activated into trypsin.