Enzymatic synthesis of inositol plasmalogens from distinct lipid sources using phospholipase D from Streptomyces antibioticus.

Plasmalogens are a subclass of glycerophospholipids characterized by a vinyl-ether bond at the sn-1 position; they play several physiological roles including membrane stabilization, antioxidant activity, and signal transduction. While choline, ethanolamine, serine, and glycerol plasmalogens (PlsCho, PlsEtn, PlsSer, and PlsGro) are naturally abundant, inositol plasmalogens (PlsIns) are rare. In contrast to the limited occurrence of PlsIns, phosphatidylinositol is a biologically crucial lipid, and its enzymatic biosynthesis from phosphatidylcholine has been extensively studied. Given that inositol itself is known to exert a range of physiological effects, it is reasonable to expect that PlsIns may also possess distinctive biological functions. Here, we report the first enzymatic synthesis of PlsIns using a phospholipase D-mediated transphosphatidylation reaction. Plasmalogen substrates-PlsEtn from Selenomonas ruminantium and both PlsEtn and PlsCho from chicken breast-were successfully converted to novel PlsIns species in the presence of myo-inositol. The resulting plasmalogens were detected by liquid chromatography-tandem mass spectrometry, confirming the introduction of the inositol moiety into the head group region. The results indicated that our method can be applied to different types of plasmalogens with different head groups and fatty acid profiles, including chain length and degree of unsaturation. This finding opens new avenues for exploring PlsIns and their potential biosignificance.