Cardiolipin and other phospholipids in ox liver

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Abstract
The polyglycerophosphatide of ox liver isolated by chromatography on silicic acid and by solvent fractionation of barium salts was identified as cardiolipin by the similarity in chromatographic and chemical properties of the phospholipids and of the phosphoric esters derived from them by mild alkaline hydrolysis. The Feulgen reaction given by crude cardiolipin fractions is attributed to the presence of rancid phosphatides, whose amount is small in relation to the total phospholipid. Degraded phosphatides were present in the fraction expected to contain phosphatidic acid. It were therefore considered impossible either to exclude or confirm the presence of naturally occurring phosphatidic acid. The bearing of these facts on the isolation of phosphatidic acid reported by Hubscher and Clark (1960) is discussed. Linoleic acid (70%) and llnolenic acid (12-15%) were the main fatty acids in ox liver cardiolipin. Phosphatidylinositol isolated in yields of 64-70% of the total inositide contained stearic acid as virtually the only satura- ted acid (45-55%) and polyenoic acids in varying proportion as the main unsaturated components. Successive fractions of liver lecithin with decreasing iodine values obtained by chromatography on silicic acid contained similar proportions of saturated acids and decreasing proportions of polyenoic acids.