Option (A) provides the correct matching for enzyme components: P-4, Q-5, R-2, S-3.
This aligns with standard biochemistry definitions where coenzyme is a cofactor, holoenzyme combines apoenzyme with prosthetic group, prosthetic group is the non-protein part, and apoenzyme is purely protein.​

Definitions and Matching

• P. Coenzyme → 4. Cofactor in an enzymatic reaction: Coenzymes (e.g., NAD+) are organic cofactors that assist catalysis, loosely bound unlike prosthetic groups.​

• Q. Holoenzyme → 5. Apoenzyme + Prosthetic group: Complete active enzyme = protein (apoenzyme) + tightly bound non-protein (prosthetic group like heme).​

• R. Prosthetic group → 2. Non-protein part in an active enzyme: Dialyzable, thermostable, covalently/tightly bound cofactors (e.g., FAD in succinate dehydrogenase).​

• S. Apoenzyme → 3. Only the protein part in an active enzyme: Inactive protein moiety needing cofactor for activity.​

Option Breakdown

• (A) P-4, Q-5, R-2, S-3: Correct—all match precisely.​

• (B) P-4, Q-3, R-1, S-2: Wrong—Q ≠ apoenzyme alone; R ≠ holoenzyme + apoenzyme (nonsensical).

• (C) P-4, Q-3, R-5, S-6: Wrong—Q ≠ protein only; S ≠ holoenzyme + phosphate (irrelevant).

• (D) P-4, Q-1, R-3, S-5: Wrong—Q ≠ holoenzyme + apoenzyme (circular); S ≠ holoenzyme itself.

Introduction to Coenzyme Holoenzyme Prosthetic Group Apoenzyme

Coenzyme holoenzyme prosthetic group apoenzyme matching tests enzyme structure in GATE Life Sciences. Holoenzyme (apoenzyme + prosthetic group) is active; coenzyme acts as transient cofactor. Q.64 option (A) perfectly aligns definitions.​

Correct Matching Breakdown

Why Other Options Fail

(B,C,D) mismatch holoenzyme (not just protein) and invent invalid combos like “holoenzyme + phosphate.”​

GATE Prep Tip

Memorize coenzyme holoenzyme prosthetic group apoenzyme via mnemonics: “HAP” (Holo = Apo + Prosthetic). Master for biochemistry PYQs.