Application Notes:
15-Methylhexadecanoic acid is present in many plants, animals, and other organisms and has a central role in the
biosynthesis of other iso-fatty acids in Stigmatella aurantiaca.1 In bacteria, the iso-fatty acid2 content and composition can
often be used as a taxonomic marker3 because iso-fatty acids are often found in bacteria but not commonly in other
microorganisms. Some bacteria have iso- but not anteiso-fatty acids while others have anteiso- but not iso-fatty acids. Isofatty
acids are found in small amounts in marine organisms and ruminants, mainly due to the food chain but also due to some
de novo synthesis. Iso-fatty acids with a total even number of carbons are more common than a total odd number. Some waxy
materials such as lanolin, as well as secretions near animal eyes, contain an unusually high amount of iso-fatty acids being
employed for their lubricating effect. Branched chain fatty acids are critical for the regulation of fluidity in membranes and in
membrane transport for many types of bacteria due to their having a significantly lower transition temperature than straight
chain fatty acids. Some bacteria handle stress (such as heat and toxicity) by changing the ratio of anteiso/iso-fatty acids in the
cell membrane. Iso-fatty acids have been found to be activators for various enzymes and systems and are used as protein
modifiers. Although iso-even chain fatty acids are commonly derived from isobutyryl-CoA some bacteria derive all iso-even
chain fatty acids via alpha-oxidation of iso-odd chain fatty acids.4 While iso-fatty acids are not usually found in plant oils the
waxy surface of leaves can contain significant amounts of these fatty acids.
References:
1. J. Dickschat et al. “Biosynthesis of iso-fatty acids in myxobacteria” Organic and Biomolecular Chemistry, Vol. 3 pp. 2824-2831, 2005
2. T. Kaneda “Iso- and Anteiso-Fatty Acids in Bacteria: Biosynthesis, Function, and Taxonomic Significancet” American Society for Microbiology, Vol. 55(2) pp. 288-302, 1991
3. N. Jensen and M. Gross “Fast Atom Bombardment and Tandem Mass Spectrometry for Determining Iso- and Anteiso-Fatty Acids” Lipids, Vol. 21(5) pp. 362-365, 1986
4. H. Bode et al. “Biosynthesis of Iso-Fatty Acids in Myxobacteria: Iso-Even Fatty Acids Are Derived by a-Oxidation from Iso-Odd Fatty Acids” J. Am. Chem. Soc., Vol. 127(2) pp 532–533, 2005