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Studies of triacyglycerol structure of very low density lipoproteins of normolipemic subjects and patients with type III and type IV hyperlipoproteinemia
Author(s) -
Myher J. J.,
Kuksis A.,
Breckenridge W. C.,
Little J. A.
Publication year - 1984
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02534528
Subject(s) - chemistry , chromatography , very low density lipoprotein , lipidology , fatty acid , composition (language) , silica gel , thin layer chromatography , organic chemistry , biochemistry , lipoprotein , cholesterol , linguistics , philosophy
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 gasliquid 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.