The possible functional significance of phosphatidylethanolamine methylation

Abstract

In view of the relatively minor importance of the methylation pathway in phosphatidylcholine biosynthesis in liver, the reports of significant physiological changes attributed to phospholipid methylation were considered. Calculations show that this enzymatic activity in [rat] reticulocytes, erythrocytes and mammary gland membranes is 0.1% of that observed in [rat] liver microsomes. Furthermore, in conditions where marked changes in microviscosity of the erythrocyte membrane were observed, only extremely small amounts of phosphatidylethanolamine were methylated. For these and other reasons, there is considerable doubt that methylation of phosphatidylethanolamine could account for the many physiological responses attributed to this activity.