Phenylethanolamine N-methyltransferase (PNMT) is an enzyme found in the adrenal medulla that converts norepinephrine (noradrenaline) to epinephrine (adrenaline).
PNMT is positively influenced by cortisol, which is produced in the adrenal cortex.
S-adenosyl-L-methionine (SAM) is a required cofactor. PNMT catalyzes the transfer of a methyl group from SAM to norepinephrine, converting it into epinephrine. This enzyme also converts phenethylamine to N-methylphenethylamine, an isomer of amphetamine.
PNMT plays an important role in trace amine and catecholamine biosynthesis.