This enzyme belongs to the family of transferases, specifically those transferring one-carbon group methyltransferases. The systematic name of this enzyme class is S-adenosyl-L-methionine:phosphatidyl-N-methylethanolamine N-methyltransferase. Other names in common use include phosphatidylmonomethylethanolamine methyltransferase, methyltransferase II, phospholipid methyltransferase, PLMT, phosphatidyl-N-methylethanolamine methyltransferase, phosphatidyl-N-monomethylethanolamine methyltransferase, phosphatidylethanolamine methyltransferase I, and phosphatidylmonomethylethanolamine methyltransferase. This enzyme participates in glycine, serine and threoninemetabolism and glycerophospholipidmetabolism.