Question

Given below are two statements
Statement I: Both lactoferrin and lactoperoxidase have antimicrobial potential
Statement II: Human milk is a rich source of both lactoferrin and lactoperoxidase
In light of the above statements, choose the correct answer from the options given below:

• A. Both Statement I and Statement II are true
• B. Both Statement I and Statement II are false
• C. Statement I is true but Statement II is false
• D. Statement I is false but Statement II is true

Hint:

Remember this species difference: - Human milk $\rightarrow$ High in Lactoferrin, low in Lactoperoxidase. - Cow milk $\rightarrow$ High in Lactoperoxidase, low in Lactoferrin.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Lactoferrin and lactoperoxidase are protective whey proteins found in mammalian milk that contribute to the innate immune system of the newborn.
While both have antimicrobial properties, their concentrations vary significantly between mammalian species.

Step 2: Detailed Explanation:
Let us evaluate both statements:
- Statement I: Both proteins are well-documented antimicrobial agents.
Lactoferrin is an iron-binding glycoprotein that sequester free iron ($Fe^{3+}$), depriving iron-dependent pathogens of this essential nutrient and inhibiting their growth.
Lactoperoxidase is an enzyme that catalyzes the hydrogen peroxide-dependent oxidation of thiocyanate to produce hypothiocyanite, a potent oxidizing agent that damages bacterial cell membranes. Thus, Statement I is true.
- Statement II: Human milk contains very high levels of lactoferrin (about 0 to 0 g/L).
However, it contains extremely low, near-negligible levels of lactoperoxidase.
In contrast, bovine (cow) milk is a rich source of lactoperoxidase (about 30 mg/L) but has very low levels of lactoferrin (about 0.1 g/L).
Therefore, human milk is not a rich source of both proteins, making Statement II false.
Consequently, Statement I is true but Statement II is false.

Step 3: Final Answer
The correct option is (C).