CHAPTER 24: Unit 12. Fatty Acids Synthesis Cycle Redundancy

Fatty acids synthesis Cycle repeat can undergo 4 reactions steps:      1. Condensation:Acetate (2C) and malonate (3C), are combined to produce acetyl-ACP and malonyl-ACPThe non-ACP-bound carboxyl group of malonate as CO2 is releasedβ-acetoacetyl-ACP (4C) is produced2. Reduction:β-hydroxybutyryl-ACP (4C) is produced with the oxidation of NADPH2 to NADP+3. Dehydration:Crotonyl-ACP (4C) reaction produces the release water4. Reduction:Butyrl-ACP is produced with the oxidation of NADPH2 to NADP+5. Repeat:Butyrl-ACP then enters into reaction 1 in the place of malonyl-ACP, undergoing the addition of another two carbons from acetate.The overall reaction uses 8 acetyl CoA, 14 NADPH, 14 H+ and 1 malonyl CoA to produce a 16-carbon palmitic acid.

The video illustrates the fatty acids synthesis cycle repeat:

The figure below shows the fatty acids synthesis cycle repeat.
Reference: https://www.biochemden.com/biosynthesis-saturated-fatty-acids-notes/
Important Notes Regarding the Fatty Acids Synthesis:Shorter fatty acids chains are released before the long fatty acids chains (with more than 16 carbon atoms) in the fatty acids synthesis process. The longer fatty acids are released with enzymes that add 2 carbon atoms of acetyl units to the carboxyl end of the fatty acid chains.Fatty acids synthesis is carried out in the adipose tissues where triacylglycerols are stored for future need. Insulin helps the formation of fatty acids. Insulin moves glucose into the cell when blood glucose is very high. Furthermore, insulin helps the glycolysis process and the oxidation of pyruvate and acetyl CoA needed for the fatty acids synthesis.β oxidation takes out 2 carbon acetyl units from long carbon chains. The fatty acids synthesis combines the 2 carbon acetyl units to make long carbon chains.