Question

Which of the following are true about chymosin?
(A) is commonly known as rennin
(B) is used in cheese industry
(C) is a protease enzyme
(D) is an essential amino acid

• A. (A), (B) and (D) only.
• B. (A), (B) and (C) only.
• C. (A), (B), (C) and (D).
• D. (B), (C) and (D) only.

Hint:

Chymosin (rennin) is an enzyme (which is a protein catalyst), not an amino acid (which are the building blocks of proteins). This distinction helps eliminate options containing (D).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Chymosin is a proteolytic enzyme historically sourced from the abomasum (fourth stomach) of unweaned calves.
It serves as the active component in traditional rennet preparations used for milk coagulation.

Step 2: Detailed Explanation:
Let us evaluate each of the statements regarding chymosin:
- Statement (A) is true: Chymosin is widely and traditionally known as rennin. (Note: It should not be confused with renin, which is an endocrine enzyme produced by the kidneys).
- Statement (B) is true: It is the primary coagulant used in the cheese industry.
Its high specificity for \(\kappa\)-casein minimizes non-specific proteolysis, resulting in high cheese yields and preventing bitter flavors during ripening.
- Statement (C) is true: Chymosin is an aspartic protease enzyme (EC 3.4.23.4).
It catalyzes the cleavage of the Phe\(_{105}\)-Met\(_{106}\) peptide bond of \(\kappa\)-casein, which destabilizes the colloidal suspension of casein micelles.
- Statement (D) is false: Chymosin is a complex, multi-subunit globular protein consisting of \(323\) amino acids.
It is a functional macromolecular enzyme, not a single monomeric essential amino acid (such as lysine or methionine).

Step 3: Final Answer:
Statements (A), (B), and (C) are correct, which corresponds to (A), (B) and (C) only.