Structure of plasmalogen (PL) and the corresponding phospholipid used in this study. In the plasmalogens, the fatty acid is linked via an enol ether bond instead of an ester bond marked in red. Residue 1 (R1) can either be a phosphatidylcholine or a phosphatidylethanolamine leading to PC-plasmalogen or PE-plasmalogen. The sn-2 position can vary in different fatty acids symbolized by residue 2 (R2).