(2R,3S)-2,4',7-trihydroxyisoflavanone + S-adenosyl-L-methionine = (2R,3S)-2,7-dihydroxy-4'-methoxyisoflavanone + S-adenosyl-L-homocysteine + H(+)
(2r,3s)-2,4',7-trihydroxyisoflavanone + s-adenosyl-l-methionine = (2r,3s)-2,7-dihydroxy-4'-methoxyisoflavanone + s-adenosyl-l-homocysteine + h(+)