Fatty Acid Synthesis  (Further elongation)

Although palmitate, a 16-carbon, fully saturated LCFA (16:0), is the primary end product of FAS activity, it can be further elongated by the addition of two-carbon units to the carboxylate end primarily in the smooth endoplasmic reticulum (SER). Elongation requires a system of separate enzymes rather than a multifunctional enzyme. Malonyl CoA is the twocarbon donor, and NADPH supplies the electrons.

The brain has additional elongation capabilities, allowing it to produce the very-long-chain fatty acids ([VLCFA] over 22 carbons) that are required for synthesis of brain lipids.