label: (S)-norprotosinomenine + S-adenosyl-L-methionine <=> (S)-6-O-methylnorprotosinomenine + S-adenosyl-L-homocysteine + H(+)
label_lc: (s)-norprotosinomenine + s-adenosyl-l-methionine <=> (s)-6-o-methylnorprotosinomenine + s-adenosyl-l-homocysteine + h(+)