The methylation of phosphatidylethanolamine is an auxiliary pathway for phosphatidylcholine biosynthesis in liver. Two forms of the enzyme, phosphatidylethanolamineN‐methyltransferase, which catalyses this reaction, are located on the endoplasmic reticulum and mitochondria‐associated membranes. Both forms are encoded by a single murine gene,Pempt, located on chromosome 11. The expression of the gene begins at birth. An inverse relationship exists between the rate of liver growth and the expression of phosphatidylethanolamineN‐methyltransferase. However, disruption of thePemptgene does not alter liver growth in mice or cause any other obvious phenotype. Curr Opin Lipidol 9:125–130. © 1998 Rapid Science Ltd