Synthesis of fatty acids

Lesson 22 : Fatty Acid Synthesis

Synthesis of fatty acids

Synthesis of fatty acids involve the following steps:

  • Synthesis of malonyl-CoA via Acetyl-CoA Carboxylase
  • Fatty Acid Synthase complex
  • Fatty acid elongation and desaturation

The input to fatty acid synthesis is acetyl-CoA, which is carboxylated to malonyl-CoA.

The ATP-dependent carboxylation provides energy input. The CO2 is lost later during condensation with the growing fatty acid. The spontaneous decarboxylation drives the condensation.

Acetyl-CoA Carboxylase catalyzes the 2-step reaction by which acetyl-CoA is carboxylated to form malonyl-CoA.

As with other carboxylation reactions (e.g., Pyruvate Carboxylase), the enzyme prosthetic group is biotin.

The overall reaction, which is is spontaneous, may be summarized as:

HCO3- + ATP + acetyl-CoA à ADP + Pi + malonyl-CoA

Biotin is linked to the enzyme by an amide bond between the terminal carboxyl of the biotin side chain and the e-amino group of a lysine residue

NADPH as electron donor in the two reactions involving substrate reduction. The NADPH is produced mainly by the Pentose Phosphate Pathway

Last modified: Monday, 19 March 2012, 9:28 AM