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:(S)-scoulerine 9-O-methyltransferase. This enzyme participates in alkaloid biosynthesis i.
Muemmler S, Rueffer M, Nagakura N, Zenk MH (1985). "S-Adenosyl-L-methionine:(S)-scoulerine 9-O-methyltransferase, a highly stereo- and regiospecific enzyme in tetrahydroberberine biosynthesis". Plant Cell Reports4: 36–39. doi:10.1007/BF00285501.