Suitability ofGeotrichum candidum lipase for the stereospecific analysis of some triglycerides.

A procedure is described for determining the stereospecific structure of triacid triglycerides containing oleic acid. The method utilizes the unique specificity of the lipase system fromGeotricum candidum for hydrolyzing fatty acids which containcis-9-unsaturation.The procedure involves a pancreatic lipase hydrolysis of 10-20 mg of substrate to determine the fatty acids in the beta-position and the incubation of another 50 mg of triglyceride withG. candidum lipase to obtain diglyceride for further treatment. The alpha,alpha- and alpha,beta-diglycerides are collected separately, converted to phenyl phosphatides and treated with phospholipase A. The analysis of the monoglycerides, produced with pancreatic lipase and the analysis of the beta-lysophosphatides allows the determination of the ratios of the original 2 position oleic acidsn-triglycerides while the analysis of the alpha-lysophosphatides aids in the determination of the originalsn-triglycerides which contained oleic acid in the 3 position. The 1 position oleic acidsn-triglycerides are calculated by difference.Racemic and enantiomeric triglycerides containing palmitic, stearic and oleic acids were synthesized and used to establish the limits of the new method. The good agreement between the actual and observed values for a mixture of isomers indicates that the procedure will be useful in the analysis of triacid triglycerides which contain oleic acid. The application of the procedure to triacid triglycerides which contain other unsaturated fatty acids is discussed.