Question

How does cleavage of pepsin, trypsin, and chymotrypsin regulate enzyme activity?

a) Cleavage activates these enzymes, enhancing their catalytic activity.

b) Cleavage inactivates these enzymes, reducing their ability to catalyze reactions.

c) Cleavage alters the substrate specificity of these enzymes, affecting the types of molecules they can bind to.

d) Cleavage has no impact on enzyme activity.

Answer 1

Cleavage activates pepsin, trypsin, and chymotrypsin, enhancing their catalytic activity and allowing them to digest proteins into peptides and amino acids. This regulates their function, ensuring they are active only when needed for digestion.

Step-by-step explanation:

The cleavage of the zymogens pepsinogen, trypsinogen, and chymotrypsinogen into their active forms pepsin, trypsin, and chymotrypsin serves as a crucial regulatory mechanism for enzyme activity within the digestive system. When activated by cleavage, these enzymes begin to catalyze the hydrolysis of peptide bonds in proteins, enabling the digestion process. Specifically, pepsin is activated in the acidic environment of the stomach to break down proteins into peptides. In the duodenum, the enzyme enteropeptidase converts trypsinogen to trypsin, which in turn activates chymotrypsinogen to chymotrypsin. These enzymes, now active, further catalyze the breakdown of proteins into smaller peptides and eventually into amino acids, which are absorbed into the bloodstream. This system ensures that the enzymes are only active when necessary, preventing unwanted proteolysis within the cells where they are produced.