IDENTIFICATION OF A NEW SPHINGOLIPID 3-O-ACYL-D-ERYTHRO-SPHINGOMYELININ NEWBORN PIG AND INFANT PLASMA

A new sphingolipid was found in newborn pig plasma at a level of 2.5 /- 0.4% of total lipids. The compound decreased to less than half that amount by day one of age and virtually disappeared by the fourth week . On thin-layer chromatography (TLC) the new lipid migrated close to p hosphatidylethanolamine. The compound was isolated by TLC from the pla sma of newborn piglets and identified as a 3-O-acyl-D-erythro-sphingom yelin by chemical and chromatographic techniques. H-1- and C-13-nuclea r magnetic resonance and fast-atom bombardment mass spectrometry. Mild alkaline hydrolysis at room temperature gave mainly C-16 and C(1)8 fa tty acids and sphingomyelin. Subsequent reaction with Ba(OH)(2) releas ed long-chain saturated and monounsaturated fatty acids from C-14 to C -24, and sphingosine which was identified as the erythro configuration by gas chromatography. Less than 1% of the sphingosine was of the C-2 0 isomer. No hydroxy fatty acids were found. The acylated sphingomyeli n was only found in plasma lipids of newborn piglets and not in their red blood cell membranes or platelets of newborn piglets, or in sow pl asma. This compound was tentatively identified by chromatography in tr ace amounts in the serum of cord blood of newborn infants, but not in the plasma lipids of adults.