Resolution of molecular species of intact serine and ethanolamine phosphatides by argentation chromatography of their trifluoroacetamides

Abstract

An effective resolution of intact phosphatidylserines on the basis of unsaturation has been achieved by conventional argentation thin layer chromatography (TLC) following trifluoracetylaction. The trifluoroacetamides are prepared by treatment with trifluoroacetic anhydride or N-methyl-bis-trifluoroacetamide. The acetamides are resolved with chloroform-methanol-water (65:25:4, v/v/v) on Silica Gel G containing 20% silver nitrate. Subfractions with 0-6 double bonds per molecule were obtained for the phosphatidylserines of pig and ox brain, pig erythrocytes, rat liver, and rabbit skeletal muscle. The preparation of trifluoroacetamides is also advantageous for the silver ion fractionation of phosphatidylethanolamines. The method is applicable to metabolic studies of molecular species using radioactive precursors of neutral lipids, phosphorus, and nitrogenous bases.

Phospholipid substrate-specificity of the l-serine base-exchange enzyme in rat liver microsomal fraction

“…CoA and arachidonoyl-CoA (Holub, 1980). As 30% and 50% of the microsomal and total liver phosphatidylserines respectively are saturatedhexaenoic species, and as they also contain 15 times more stearic acid than palmitic acid (Yeung et al, 1977;Bjerve, 1982), this indicates that the Lands & Merkl (1963) pathway does not play any quantitatively significant role in the biosynthesis of rat liver phosphatidylserines. Other, energy-requiring, pathways of phosphatidylserine synthesis have been suggested to explain some observed phenomena in systems investigated in vitro (Hiibscher et al, 1959;Bygrave & Bucher, 1968;Baranska, 1980).…”

“…Approx. 45% of the phosphatidylserines in the rat liver cell are stearoyl-docosahexaenoyl species, and 30% are stearoyl-arachidonoyl species (Yeung et al, 1977;Bjerve, 1982). It has been suggested that the arachidonoyl species are synthesized mainly by re-acylation of l-acyl-sn-3-glycerophos-* Present address.…”