Consider the following statement : (A) Coenzyme or metal ion that is tightly bound to enzyme protein is called prosthetic group. (B) A complete catalytic active enzyme with its bound prosthetic group is called apoenzyme. Select the correct option.
Answer: (C) Both (A) and (B) are false.. Answer: (C) Both (A) and (B) are false.
- A.Both (A) and (B) are true.
- B.(A) is true but (B) is false.
- C.Both (A) and (B) are false.✓
- D.(A) is false but (B) is true.
Correct Answer
(C) Both (A) and (B) are false.
Solution & Explanation
Answer: (C) Both (A) and (B) are false. Solution: Statement (A) is false because a tightly bound cofactor is specifically the PROSTHETIC GROUP only when it is an organic compound; the general definition given (any coenzyme OR metal ion tightly bound) is incorrect — coenzymes associate only transiently and prosthetic groups are the tightly-bound organic ones. Statement (B) is false because a complete active enzyme with its bound prosthetic group/cofactor is the HOLOENZYME, not the apoenzyme (the apoenzyme is only the protein portion). Hence both statements are false. NCERT Reference: Ch 9, p.118, line ~6 — "Prosthetic groups are organic compounds and are distinguished from other cofactors in that they are tightly bound to the apoenzyme"