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I. Frequently Asked Questions about Fatty Acid Metabolism

                                                           

Fatty Acid Nomenclature: Answer

How are fatty acids named? How is the position of a double bond indicated? How does the omega nomenclature system work?

The most abundant fatty acids are generally called by their nonsystematic common names. Persons who will be working with these fatty acids will learn the common nomenclature whether they approve of it or not.

Positions of double bonds are always designated by the number of the involved carbon that is closest to the reference point. For example, in the IUPAC system and the Delta abbreviation system, the reference point (numbered 1) is the carboxyl carbon. Hence a double bond in the 9-position, which is the same as a ⁹ double bond, is between the 9-carbon and the 10-carbon. In the omega system the reference point is the last carbon in the chain, farthest from the carboxyl carbon. An omega - 3 (omega minus three) double bond joins the third carbon from that end to the fourth carbon from that end.