(R)-norprotosinomenine + S-adenosyl-L-methionine => (R)-6-O-methylnorprotosinomenine + S-adenosyl-L-homocysteine + H(+)
(r)-norprotosinomenine + s-adenosyl-l-methionine => (r)-6-o-methylnorprotosinomenine + s-adenosyl-l-homocysteine + h(+)