Saturday, October 5, 2013

FATTY ACIDS SYNTHEIS


Fatty acid synthesis is the creation of fatty acids from acetyl-CoA and malonyl-CoA precursors through action of enzymes called fatty acid synthases. It is an important part of the lipogenesis process, which – together with glycolysis – stands behind creating fats from blood sugar in living organisms.

Acetyl-CoA

  • Acetyl CoA molecules are the building blocks of fatty acid synthesis.
  • Fatty acids are constructed by the addition of two carbon units derived from acetyl-CoA.
  • In each step acetyl CoA are added, thus addition of 8 acetyl-CoA units results into the Palmitic acid synthesis.
 Malonyl-CoA
  • The acetate units are activated for fatty acid biosynthesis by the formation of malonyl-CoA at the expense of ATP.
  • Malonyl-CoA plays a key role in chain elongation in fatty acid biosynthesis. This coenzyme is produced from the addition of carbon dioxide to Acetyl-CoA. The role of Malonyl-CoA in fatty acid biosynthesis is to provide growing fatty acid chains with two units of carbon.
  • Malonyl-CoA carbons becomes COOH end in the fatty acids synthesis.
  • The driving force for the addition of two carbon units to the growing chain is the decarboxylation of malonyl-CoA.
The Design Strategy for Fatty Acid Biosynthesis.
  • The chain elongation stops at palmitoyl-CoA.
  • Other enzymes add double bonds or additional carbon atom to the carbon chain.





Naturally occurring fatty acids share a common biosynthesis. The chain is built from two carbon units, and cis double bonds are inserted by desaturase enzymes at specific positions relative to the carboxyl group. This results in even-chain-length fatty acids with a characteristic pattern of methylene interrupted cis double bonds.

SOURCES OF FATTY ACIDS: 


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