Question

Describe the digestive role of chymotrypsin. Which two other digestive enzymes of the same category are secreted by its own source gland?

Answer 1

Hint: The breakdown (hydrolysis) of food molecules into their 'building block' components is accelerated by digestive enzymes. These reactions take place outside the cells lining the intestine.

Complete answer:
Chymotrypsinogen is an inactive enzyme which is activated by the action of enzyme trypsin present in the pancreatic juice into chymotrypsin. Chymotrypsin plays a significant role in the breakdown of partially hydrolysed proteins into peptides when activated.

The majority of the same group of digestive enzymes are trypsinogen and carboxypeptidase. These are secreted by the same pancreas, source-gland.

Trypsinogen is present in the pancreatic juice in an inactive form. The enterokinase enzyme-secreted by the mucosa of the intestine-activates trypsinogen into trypsin. The trypsin then triggered the existing trypsinogen and enabled other pancreatic enzymes, like chymotrypsinogen and carboxypeptidase, to further hydrolyse. Trypsin is also useful in breaking down proteins into peptides.

Carboxypeptidases function on the peptide chain's carboxyl end and help release the latter amino acids. They are present in pancreatic juice and split into dipeptides proteins and peptones and proteoses.

Additional information:
The hydrolysis of peptide bonds is catalysed by protease enzymes. Catalysis promotes an activated water molecule's nucleophilic attack on the peptide bond. Trypsin can cleave several proteins into smaller fragments, whereas enzymes such as thrombin, which is involved in blood clotting, are highly specific, varying from general to specific, e.g. digestive protease enzymes. Many protease enzymes exist in an inactive type. These precursors, being protein itself, are converted into an active form by another protease enzyme. It assists in the regulation and control of the activity. Trypsinogen, chymotrypsinogen, procarboxypeptidase, proelastase, are some examples.

Note: These enzymes are present in all living species, such as bacteria, algae, plants, animals, and also in some viruses. They are involved in protein catabolism and digestion and also in the signalling of cells.