Mammalian fatty acid synthase is a multifunctional homodimer. Regardless of the chain length of the starting acyl group or the duration of synthesis, what is the sole free fatty acid released by the mammalian enzyme complex after thioesterase action?

• A Myristate (C14:0)
• B Palmitoleate (C16:1)
• C Stearate (C18:0)
• D Palmitate (C16:0) ✓

Explanation

The mammalian fatty acid synthase carries an intrinsic thioesterase domain that releases only palmitate (D16:0) after seven cycles of two-carbon addition on the acyl carrier protein. Longer chains such as stearate require separate elongase enzymes in the endoplasmic reticulum or mitochondria, and monounsaturated products like palmitoleate require delta-9 desaturase, which kills options B and C.

Reference: Lippincott's Illustrated Reviews: Biochemistry, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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