THE BIOSYNTHESIS AND FUNCTIONS OF PLASMALOGENS

The biosynthesis of plasmalogen (alkenyl acyl glycerophosphoryl cholin e or ethanolamine) is independent of diacyl glycerophospholipid synthe sis and requires the coordinated activities of peroxisomal, cytosolic, and endoplasmic reticulum enzymes. This would indicate that the plasm alogens may have a unique role(s) to play in cellular functions, one d ifferent from that of the diacyl glycerophospholipids. Several functio ns have been assigned to plasmalogens such as antioxidants, arachidoni c acid storage terminals, receptor mediators, substrate for the biosyn thesis of platelet-activating-factor (PAF), and determinant of physico chemical properties of biomembranes. Except for serving as a substrate for biologically active PAF biosynthesis, none of the proposed functi ons have been fully validated. The purpose of this review article is t o provide up-to-date knowledge of the biosynthetic pathway and functio ns of plasmalogens.