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THE MASS DISTRIBUTION OF THE PHOSPHATIDYLCHOLINES IN SUBCELLULAR FRACTIONS OF RAT BRAIN 1
Author(s) -
O'Brien J. F.,
Geison R. L.
Publication year - 1971
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1971.tb03735.x
Subject(s) - phosphatidylcholine , chemistry , diglyceride , chromatography , gas chromatography , myelin , hydrolysis , fatty acid , polyunsaturated fatty acid , trimethylsilyl , phospholipase , biochemistry , phospholipid , organic chemistry , membrane , enzyme , biology , central nervous system , neuroscience
Abstract Whole brains from 20‐22‐day‐old rats were separated into the 15,000 g supernatant, myelin, nerve ending and mitochondrial fractions. Gas chromatography of the trimethylsilyl derivatives of 1,2‐diglycerides obtained by hydrolysis with phospholipase C of the phosphatidylcholine from each fraction showed marked differences of carbon number distribution (i.e. the sum of the carbon atoms in the two fatty acids of the diglyceride) among the different membranous fractions. Further characterization of each diglyceride was obtained by preparative gas chromatography of the diglyceride‐trimethylsilyl ethers and determination of the acyl moieties after collection, methanolysis and gas chromatography. The results indicate that at least three distinct populations of phosphatidylcholine exist in the brain. Nerve endings and the 15,000 g supernatant fraction exhibit a very similar diglyceride pattern with dipalmitoylglycerophosphorylcholine representing over 30 per cent of the species present. Myelin has a unique phosphatidylcholine composition with much less polyenoic species in the 36 and 38 carbon number peaks. Mitochondria contain phosphatidylcholines with relatively more long‐chain polyunsaturated fatty acids. TLC of the phosphatidylcholines yielded partial separation into two spots, which differed in distribution of fatty acids. The faster migrating spot contained most of the polyenoic acids, whereas the slower migrating spot contained most of the palmitic, stearic and oleic acids.