OCCURRENCE OF WAX ESTERS AND 1-O-ALKYL-2,3-DIACYLGLYCEROLS IN GOAT EPIDIDYMAL SPERM PLASMA-MEMBRANE

Two unusual lipid classes were detected by thin-layer chromatography in the neutral lipids derived from goat cauda-epididymal sperm plasma membrane. The lipids were identified as wax esters and 1.0-alkyl-2,3-diacylglycerols based on chromatographic properties, identity of their hydrolysis products, and infrared/H-1 nuclear magnetic resonance spectral evidence. The membrane contained ca. 3 and 5-mu-g/mg protein of wax esters and alkyldiacylglycerols, respectively. The relative proportions of wax esters and alkyldiacylglycerols in the total neutral lipids were 1.5% and 2.4%, respectively. The lipids contained fatty acids with chain lengths of C-14 to C22. The major fatty acids of the wax esters were 14:0, 16:0, 16:1-omega-7, 18:0 and 18:1-omega-9. The fatty acids in alkyldiacylglycerol were 16:0, 18:0, 22:5-omega-3 and 22:6-omega-3. Alkyldiacylglycerol was particularly rich in docosahexaenoic acid (22:6-omega-3) representing 30% of the total fatty acids. The alcohols of wax ester were all saturated with C20-C29 carbon chains. The deacylated products derived from alkyldiacylglycerols were identified as hexadecyl, octadecyl and octadec-9'-enyl glycerol ethers.