The quantitative determination of plasmalogen by its reaction with mercuric chloride.

The alk-1-enyl group of 1-alk-1(1)-enyl-2-acyl-glycerophospholipids (plasmalogens) rapidly combines with mercuric chloride. At 0 C, there was a 1:1 stoichiometry for Hg binding to the reactive enol group of plasmalogens. Aldehydes were not released, indicating that the alkenyl ether bond was not cleaved. Hg binding to less reactive double bonds in unsaturated fatty acids was not significant. Quantitative estimation of bound Hg afforded a rapid and sensitive assay for alkenylacyl lipids and gave values similar to those obtained with other methods of analysis. The proportion of plasmalogens in bovine myelin glycerophosphatides and in ethanolamine glycerophosphatide was 35 and 75%, respectively. Plasmalogens account for 23.3% of the total glycerophospholipid of rat erythrocytes.