Studies of triacyglycerol structure of very low density lipoproteins of normolipemic subjects and patients with type III and type IV hyperlipoproteinemia.
The triacylglycerols of very low density lipoproteins (VLDL-TG) were analyzed in samples from normal subjects and patients with Frederickson's Type III and Type IV hyperlipoproteinemia. VLDL were obtained by conventional ultracentrifugation, and the triacylglycerols were isolated by thin-layer chromatography (TLC). Representative sn-1,2(2,3)- and sn-1,3-diacylglycerols were generated by Grignard degradation of the triacylglycerols, and were resolved by TLC on borate-treated silica gel. The molecular association of the fatty acids in the diacylglycerol moieties was determined by gas-liquid chromatography with mass spectrometry (GC/MS) of the tertiary-butyldimethylsilyl ethers. The positional distribution of the fatty acids was established by the Brockerhoff stereospecific analysis. The results showed a marked asymmetry in the distribution of the fatty acids in all samples, with the saturated acids predominantly in the sn-1-position and the unsaturated fatty acids distributed about equally between the sn-2- and sn-3-positions. In all instances, the molecular species composition of the sn-1,2-, sn-2,3- and sn-1,3-diacylglycerols was found to be similar to that calculated for 1-random 2-random 3-random distribution of triacylglycerols. There were marked differences in the quantitative composition of the molecular species of the VLDL-TG between normal subjects and patients, but these discrepancies were attributed to differences in the fatty acid composition of the samples.
D004075:Diglycerides / Q000097:blood; D005227:Fatty Acids / Q000032:analysis; D005260:Female; D006801:Humans; D006952:Hyperlipoproteinemia Type III / Q000097:blood*; D006953:Hyperlipoproteinemia Type IV / Q000097:blood*; D008079:Lipoproteins, VLDL / Q000097:blood*; D008297:Male; D012016:Reference Values; D014280:Triglycerides / Q000097:blood*
D004075:Diglycerides; D005227:Fatty Acids; D008079:Lipoproteins, VLDL; D014280:Triglycerides