- Fatty acid synthesis
Fatty acidsare formed by the action of Fatty acid synthases from acetyl-CoAand malonyl-CoAprecursors.
De Novo Synthesis in Humans
In humans fatty acids are predominantly formed in the
liverand adipose tissue, and mammary glandsduring lactation. Most acetyl-CoA is formed from pyruvateby pyruvate dehydrogenasein the mitochondria. Acetyl-CoA produced in the mitochondria is condensed with oxaloacetateto form citrate, which is then transported into the cytosol and broken down to yield acetyl-CoA and oxaloacetateby ATP citrate lyase.
β-oxidation, elongation occurs via four recurring reactions shown below. In these diagrams, the acetyl and malonyl units are shown as their Acyl carrier proteinthioesters: this is how fatty acids are synthesized in microorganisms and plants. However, in animals these same reactions occur on a large dimeric protein, Fatty acid synthase, which has the full complement of enzymatic activities required to synthesize and liberate a free fatty acid.
In the second step of elongation,
butyrylACP condenses with malonylACP to form an acylACP compound. This continues until a C16 acyl compound is formed, at which point it is hydrolyzed by a " thioesterase" into palmitateand ACP.
* [http://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb2/part1/fasynthesis.htm Overview] at
Rensselaer Polytechnic Institute
* [http://web.indstate.edu/thcme/mwking/lipid-synthesis.html#synthesis Overview] at
Indiana State University
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