Problem 110 - Arihant Objective Approach to Organic Chemistry for IIT JEE and NEET all Medical Entrances Part 4

Question

Which of the following enzyme is not useful in the digestion of |KCET 1998| protein? (b) Chymotrypsin (a) Pepsin (c) Lipase (d) Trypsin

Step-by-Step Solution

Answer

Lipase (c) is not useful in the digestion of protein.

Step 1: Identify the enzymes listed

Let's first identify what class of enzymes each option belongs to: (a) Pepsin is a protease enzyme. (b) Chymotrypsin is also a protease. (c) Lipase is an enzyme that breaks down lipids, not proteins. (d) Trypsin is another protease enzyme.

Step 2: Determine the function of each enzyme

We need to determine which of these enzymes do not participate in protein digestion. Proteases digest proteins, so we focus on identifying which enzyme isn’t a protease.

Step 3: Evaluate the enzymes' roles

Lipase (c) is responsible for breaking down fats or lipids, not proteins. Thus, it doesn't play a role in the digestion of proteins unlike the other options (Pepsin, Chymotrypsin, Trypsin) which are all proteases involved in protein digestion.

Step 4: Choose the correct answer

Based on the evaluations, option (c) Lipase is the enzyme that is not involved in protein digestion.

Key Concepts

Enzyme Function

Enzymes are biological catalysts that significantly speed up chemical reactions in living organisms. These proteins work by lowering the activation energy needed for a reaction to proceed, ensuring that processes vital for life occur efficiently.
Enzymes play an integral role in digestion as they break down complex food molecules into simpler forms.
Key features of enzyme function include:

• Specificity: Each enzyme binds to a specific substrate or set of substrates.
• Active site: The part of the enzyme where the substrate binds and the reaction occurs.
• Environmental conditions: Enzyme activity is highly dependent on pH and temperature. Extreme changes can denature the enzyme, stopping it from functioning.
• Reusability: Enzymes are not consumed in the reaction, allowing them to be reused repeatedly.

All these characteristics make enzymes crucial for the digesting food process, as they allow the body to absorb nutrients quickly and effectively.

Protease Enzymes

Protease enzymes are specialized enzymes that break down proteins into smaller peptides and amino acids. This process, called proteolysis, is essential for protein digestion and nutrient absorption.
Pepsin, trypsin, and chymotrypsin are prime examples of proteases, each acting at different stages of digestion. Functions of protease enzymes:

• Pepsin: Operates in the acidic environment of the stomach, initiating protein breakdown.
• Trypsin: Active in the small intestine, continues the breakdown initiated by pepsin. It functions in a more alkaline environment.
• Chymotrypsin: Works alongside trypsin in the small intestine, targeting different peptide bonds.

The coordination of these enzymes ensures that proteins are efficiently converted into peptides, which are then absorbed into the bloodstream as amino acids. These amino acids are vital building blocks for the body's tissues.

Lipid Breakdown

Lipid breakdown, also known as lipolysis, involves the digestion of fats into fatty acids and glycerol. This process is crucial as it provides the body with energy and important building blocks for cell membranes.
Lipase is the key enzyme responsible for lipid breakdown. Characteristics of lipid digestion include:

• Enzyme used: Lipase is produced in the pancreas and acts in the small intestine.
• Substrate: It targets triglycerides, the main form of stored fats.
• Biliary support: Bile salts, produced by the liver and stored in the gallbladder, emulsify fats, making them accessible to lipase.
• End products: Fatty acids and glycerol are absorbed through the intestinal wall and transported via the lymphatic system.

Understanding this breakdown is vital for comprehending how the body uses dietary fats for metabolism and cellular functions.