Fatty-acyl-CoA synthase
Fatty acids are key components of a cell, therefore, the regulation or inhibition of fatty acid synthesis hold severe consequences for cellular function. The malfunction of the fatty acid synthesis pathway can result in cancer and obesity. However, the significance of fatty acid synthesis also make the fatty acid synthesis pathway a potential target for the search and study of anticancer and antibiotic drugs. It has been found that in humans, fatty acid synthase, is overly expressed in cancer cells. Therefore, FAS, which has been associated only with energy production prior, is now associated with aggressive tumor growth and survival. Studies have also found that human fatty acid synthase is overly expressed in prostate cancer cells.
Fatty acid synthesis
The branched-chain fatty acid synthesizing system uses α-keto acids as primers. This system is distinct from the branched-chain fatty acid synthetase that utilizes short-chain acyl-CoA esters as primers. α-Keto acid primers are derived from the transamination and decarboxylation of valine, leucine, and isoleucine to form 2-methylpropanyl-CoA, 3-methylbutyryl-CoA, and 2-Methylbutyryl-CoA, respectively. 2-Methylpropanyl-CoA primers derived from valine are elongated to produce even-numbered iso-series fatty acids such as 14-methyl-pentadecanoic (isopalmitic) acid, and 3-methylbutyryl-CoA primers from leucine may be used to form odd-numbered iso-series fatty acids such as 13-methyl-tetradecanoic acid. 2-Methylbutyryl-CoA primers from isoleucine are elongated to form anteiso-series fatty acids containing an odd number of carbon atoms such as 12-Methyl tetradecanoic acid. Decarboxylation of the primer precursors occurs through the branched-chain α-keto acid decarboxylase (BCKA) enzyme. Elongation of the fatty acid follows the same biosynthetic pathway in "Escherichia coli" used to produce straight-chain fatty acids where malonyl-CoA is used as a chain extender. The major end products are 12–17 carbon branched-chain fatty acids and their composition tends to be uniform and characteristic for many bacterial species.