ACYL AND ALK-1'-ENYL GROUP COMPOSITION OF ETHANOLAMINE PHOSPHOGLYCERIDES OF HUMAN BRAIN

Ethanolamine phosphogylcerides (EPG) of human brain gray and white matter were analyzed for their alk-1′-enyl group and fatty acid compositions in sn-glycerol positions 1 and 2. Gray matter contained more 18:0 (54%) and less 18:1 (24.5%) alk-1′-enyl residues than white matter (16% and 57%. Sixty per cent of alk-1′-enyl 18.1 in gray matter was the (n-7), against 71%, in white matter. Both gray and white matter contained small amounts of 18:1 (n-5) and (n-3) isomers. The fatty acids in position I of the phosphatidylethanolamines were more saturated than the corresponding alk-1′-enyl groups of the plasmalogens. The ratios of monoenoic fatty acid isomers in position 1 were markedly different from those of the corresponding alk-1′-enyl groups in gray matter. The fatty acid patterns in position 2 of plasmalogen and phosphatidylethanolamines of white matter were similar except for 22:4(n-6) which was concentrated in the plasmalogen (16% against 10%, in the phosphatidyl ethanolamine). In gray matter, the same trend was noted. The data suggest that alk-1′-enyl residues and the fatty acids in position 1 as well as the fatty acids in position 2 of alk-1′-enyl acyl and diacyl type EPG in both gray and white matter are, at least in part, of different provenance.