Fig. 4: A simplified fatty acid network including the following modules: (A) de novo synthesis of saturated fatty acids (SFA) via fatty acid synthase and a SFA elongase (B) conversion of SFA to monounsaturated fatty acids (MUFA) via ∆9 stearoyl-coA desaturase, (C) conversion of the MUFA oleic acid (18:1n-9, OA) to the n-6 PUFA linoleic acid (18:2n-6, LIN) via ∆12 methyl-end desaturase, (D) conversion of omega-6 PUFAs like LIN and arachidonic acid (20:4n-6, ARA) to the omega-3 PUFAs ALA (18:3n-3) and to EPA (20:5n-3) via the ∆15 and ∆17 omega desaturases respectively, (E) conversion of LIN to n-6 LC-PUFAs by front-end desaturases and PUFA elongases (F) conversion of ALA to n-3 LC-PUFAs by front-end desaturases and PUFA elongases. Note that Beta-oxidation process (multi-enzyme reaction) is also required to synthesise some LC-PUFA including DHA.