label: norbelladine + S-adenosyl-L-methionine <=> 4'-O-methylnorbelladine + S-adenosyl-L-homocysteine + H(+)
label_lc: norbelladine + s-adenosyl-l-methionine <=> 4'-o-methylnorbelladine + s-adenosyl-l-homocysteine + h(+)