 While PNMT methylates norepinephrine into the active compound epinephrine, norepinephrine can also be methylated by catechol-O-methyl transferase (COMT), another methyltransferase which adds a methyl group in a different location, in turn producing the inactive compound metanephrine.Methyltransferases are very common in the catecholamine synthesis and deactivation pathways.PNMT is also involved in the biosynthesis of "N"-methylated trace amines