A Study of the Oxidation of the Ammonium Salts of Normal Saturated Fatty Acids and its Biological Significance

Abstract

IN a number of papers Dakin [1908, 1, 2, 3; 1910] described the production of ,B-keto-acids and the ketones arising from them by loss of carbon dioxide, in a series of experiments on the oxidation of the ammonium salts of normal saturated fatty acids with hydrogen peroxide.The reaction is a general one and at the time it was discovered, was of great significance because it afforded great support to the evidence for the theory of ,B oxidation of fatty acids propounded by Knoop [1904].It-is a good instance of a process taking place in vtitro which has helped to throw light on a similar process occurring in the living body.The reactions which occur when fatty acids and certain of their phenyl derivatives undergo oxidation in the body are not simple.Phenyl- propionic acid has been shown by Dakin [1908, 4, 5] to yield, in addition to the corresponding fl-keto-acid, the fl-hydroxy-acid and the a, ,8-unsaturated acid.It seemed worth while therefore to find out whether Dakin's observations on the oxidation of fatty acids with hydrogen peroxide could be extended to include these other oxidation products, and especially the unsaturated acids which are sometimes formed during oxidation in living animals.Using conditions similar to but not identical with those of Dakin, attempts were made in the first instance to find out whether stearic acid yielded un- saturated acids on oxidation.At first it was thought that this was so, an acid giving a lead salt soluble in ether being isolated from the products of oxidation.This acid absorbed iodine, but not in amount sufficient to account for one double linkage, and in other ways was different from the unsaturated acids of the oleic series.The investigation of this substance has not been completed but in addition to this acid (or mixture of acids) another new acid was isolated which proved on further investigation to be y-keto-stearic acid.This showed therefore that besides ,B oxidation, y oxidation also takes place.The y-keto-acid could not be isolated quantitatively so that it is not possible to compare accurately the extent of oxidation at the f and y carbon atoms.The fl-keto-acid, under the