A rapid method for the estimation of bacterial fatty acid biosynthesis

During investigations of fatty acid metabolism in Escherichia coli, the need arose for a method to differentiate between the incorporation of C¹⁴-labeled compounds into fatty acids and the incorporation into non-lipid cell constituents. Although a solvent extraction method (1) is available that yields quantitative and reproducible results for fatty acid biosynthesis, a somewhat simpler method was required which would allow rapid processing of a large number of samples. The method reported in this paper will allow rapid measurement of only that portion of the C¹⁴-labeled compound which is incorporated into fatty acids. The assay is not affected by incorporation of the labeled compound into other cellular constituents (e.g., protein). The method is based upon the solubility of fatty acids in hexane and the virtual insolubility of the other bacterial cell constituents in hexane.