Phosphatidylethanolamine-N-Methyltransferase (PEMT)

PEMT encodes an enzyme which converts phosphatidylethanolamine to phosphatidylcholine by sequential methylation in the liver. The protein localizes to the endoplasmic reticulum and mitochondria-associated membranes. The gene is within the Smith-Magenis syndrome region on chromosome 17. Alternate splicing of this gene results in three transcript variants encoding two different isoforms.

Two isoforms of PEMT appear to exist: PEMT1, localized to the endoplasmic reticulum and generating most of the PEMT activity, and PEMT2, corresponding to the cloned cDNA, which resides on mitochondria-associated membranes. Both enzymes are capable of catalyzing all 3 methylation steps.