Wednesday, January 11, 2012
Fatty Acids and Eicosanoids
A fatty acid consists of a chain of carbon and hydrogen atoms with a carboxyl group at one end. Thus, fatty acids contain two oxygen atoms in addition to their complement of carbons and hydrogen. Because fatty acids are synthesized in the body by the linking together of two-carbon fragments, most fatty acids have an even number of carbon atoms (with 16- and 18-carbon). When all the carbons in a fatty acid are linked by single covalent bonds, the fatty acid is said to be a saturated fatty acid (because all the carbons are saturated with covalently bound H). Some fatty acids contain one or more double bonds, and these are known as unsaturated fatty acids. If one double bond is present, the acid is said to be monounsaturated, and if there is more than one double bond, polyunsaturated. Some fatty acids can be altered to produce a special class of molecules that regulate a number of cell functions. These modified fatty acids, collectively termed eicosanoids, are derived from the 20-carbon, polyunsaturated fatty acid arachidonic acid.