Question

Which of the following enzymes is not useful in the digestion of proteins?
A. Chymotrypsin
B. Pepsin
C. Trypsin
D. Lipase

Answer 1

Hint: Protein is a naturally occurring and extremely complex substance that consists of amino acid residues. Proteins are present in all living organisms. Protein is the most important essential constituent of diet because protein is the main food for bodybuilding. Enzyme is a type of protein that acts as a catalyst in many chemical and biochemical reactions.

Complete Step by Step Solution:
Enzymes are a type of protein. It helps in several biological functions. Every living organism has enzymes in their body. Some common types of enzymes are as follows

• • Amylase which is produced in the mouth.

• Pepsin which is produced in the stomach and helps in digestion.

• Trypsin which is produced in the pancreas.

• Pancreatic lipase which is produced in the pancreas.

• Deoxyribonuclease and ribonuclease which are produced in the pancreas.

Enzymes act as a catalyst. Thus enzyme also acts as a catalyst in biochemical reactions and increases the rate of the reaction without itself being used up.
Digestion of protein occurs in the stomach and duodenum by the help of three main enzymes: Pepsin, trypsin and chymotrypsin.

The enzyme pepsin is secreted by the stomach and the enzymes trypsin and chymotrypsin are secreted by the pancreas. These enzymes break down food proteins into polypeptides that are then broken down by various exopeptidases and endopeptidases into amino acids.
Thus lipase enzyme is not useful in the digestion of proteins.
So, the correct answer is D.

Note: A catalyst is a substance that increases the rate of a reaction without itself being used up. A catalyst lowers the activation energy of a reaction and increases the rate of the reaction. Protein is present in hormones, enzymes etc. Enzymes also act as a catalyst.