Mammalian fatty acid synthase is a homodimeric multifunctional enzyme in which each monomer carries all catalytic activities. The growing acyl chain shuttles between active sites while covalently attached to:
- A The phosphopantetheine prosthetic group of the acyl carrier protein domain ✓
- B Lipoamide
- C Coenzyme A
- D Thiamine pyrophosphate
Correct answer: A. The phosphopantetheine prosthetic group of the acyl carrier protein domain
Explanation
The acyl carrier protein (ACP) domain carries a 4'-phosphopantetheine arm, identical to the arm of coenzyme C, that swings the growing chain between the ketoacyl synthase, reductase, dehydratase and enoyl reductase sites. After seven rounds of two-carbon addition, palmitate is released by the thioesterase activity. Lipoamide serves this swinging-arm role in pyruvate and alpha-ketoglutarate dehydrogenase complexes, not in fatty acid synthase, and free coenzyme C never carries the growing chain.
Reference: Lehninger Principles of Biochemistry, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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