Question

Carboxypeptidase is an enzyme secreted by
A. Salivary gland
B. Stomach
C. Gallbladder
D. Intestine
E. Pancreas

Answer 1

Hint: We all know that Carboxypeptidase is secreted in the form of pro-carboxypeptidase which is converted to active carboxypeptidase in the presence of trypsin and it helps in degradation and digestion of large proteins.

Complete Answer:
- As we have learnt that digestion of carbohydrates, proteins, lipids and fats takes place in various parts of our body starting from mouth to stomach to small and large intestine in the presence of certain enzymes secreted.
- Digestion of protein is an anabolic process which is carried out by ribosomes of every cell and proteins include the formation of peptide bonds between amino acids that take place to produce new proteins.
- It does not get digested in the mouth as the mouth has no enzymes for protein digestion. Proteins are converted to protease, large peptides and peptones in the presence of Pepsin and Rennin enzymes secreted by gastric juices in the stomach.
- These products now are transported to the intestine where Pancreas secretes pancreatic juices which help in enzyme secretion. Trypsinogen the inactive form of enzyme gets converted to active Trypsin in the presence of enzyme Enterokinase. This activated trypsin now helps in conversion of inactive forms of Chymotrypsin and Procarboxypeptidase into their active forms Chymotrypsin and Carboxypeptidase respectively.
- All the active three pancreatic enzymes will now convert the protease, peptones and large peptides to small peptides and dipeptides. These products will be transported to the intestine where they will be converted to amino acids in the presence of Dipeptides and Aminopeptidase enzymes. Salivary glands secrete saliva and gallbladder secretes bile juices.

Hence the correct answer is (E).

Note: Enzymes like Aminopeptidase and Carboxypeptidase are called Exopeptidases as they remove amino acids from the ends of N-terminal and C-terminal respectively and enzymes like Pepsin and Trypsin are called Endopeptidases since they break down the polypeptide chain somewhere in the middle.