In enzymology, 3'-hydroxy-N-methyl-(S)-coclaurine 4'-O-methyltransferase () is an enzyme that catalyzes the chemical reaction
The two substrates of this enzyme are (S)-3'-hydroxy-N-methylcoclaurine and S-adenosyl methionine (SAM). Its products are (S)-reticuline and S-adenosylhomocysteine (SAH).
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:3'-hydroxy-N-methyl-(S)-coclaurine 4'-O-methyltransferase. This enzyme participates in alkaloid biosynthesis.