label: a 4'-hydroxyisoflavone + S-adenosyl-L-methionine = a 4'-methoxyisoflavone + S-adenosyl-L-homocysteine + H(+)
label_lc: a 4'-hydroxyisoflavone + s-adenosyl-l-methionine = a 4'-methoxyisoflavone + s-adenosyl-l-homocysteine + h(+)