Stereospecific analysis of triacylglycerols and major phosphoglycerides fromLipomyces lipoferus

The stereospecific distribution of fatty acids in triacylglycerols, phosphatidylcholines and phosphatidylethanolamines ofLipomyces lipoferus was determined. Position sn-1 of the triacylglycerols had a predominance of unsaturated fatty acids of which C_18∶1 (61%) was the major component. Position sn-2 of the triacylglycerols contained 88% C_18∶1 and was more unsaturated than position sn-1 by 24.6%. Position sn-3 had equal proportions of saturated and unsaturated fatty acids. Phosphatidylcholine had a quantitatively distinctive fatty acid distribution in that position sn-2 was 26.7% more unsaturated than position sn-1. In phosphatidylethanolamine, position sn-2 was 10.8% more unsaturated than position sn-1. Positions sn-1 and sn-2 of these phosphoglycerides had a different fatty acid profile from positions sn-1 and sn-2 of the triacylglycerols. These results suggest a nonrandom distribution of fatty acids in the triacylglycerols and phosphoglycerides. Because triacylglycerols and phosphoglycerides are both derived from 1,2-diacylglycerols, these data suggest two possibilities: some selectivity in utilization of species of diacylglycerols to form triacylglycerols and phosphoglycerides or modification of the triacylglycerols and phosphoglycerides after they are formed or both. This study is the first of its kind in a yeast. Presented in part at the AOCS Fall Meeting, Ottawa, Canada, September 1972.