Evidence for the participation of cytochrome b₅ in plasmalogen biosynthesis

Using a specific antibody to rat liver cytochrome b₅, ethanolamine plasmalogen (1 O alk 1' enyl 2 acyl sn glycerophosphorylethanolamine) synthesis by pork spleen microsomes is shown to require cytochrome b₅. Either NADH or NADPH could serve as a source of reducing equivalents. These results provide direct evidence for the involvement of cytochrome b₅ in plasmalogen biosynthesis from the corresponding 1 O alkyl ether and suggest a pathway analogous to the fatty acid desaturase system.