(S)-tetrahydropapaverine + S-adenosyl-L-methionine = (S)-N-methyltetrahydropapaverine + S-adenosyl-L-homocysteine + H(+)
(s)-tetrahydropapaverine + s-adenosyl-l-methionine = (s)-n-methyltetrahydropapaverine + s-adenosyl-l-homocysteine + h(+)
(S)-tetrahydropapaverine + S-adenosyl-L-methionine = (S)-N-methyltetrahydropapaverine + S-adenosyl-L-homocysteine + H(+)
(s)-tetrahydropapaverine + s-adenosyl-l-methionine = (s)-n-methyltetrahydropapaverine + s-adenosyl-l-homocysteine + h(+)