(3R)-3-hydroxy-2,3-dihydrotabersonine + A <=> (3R)-1,2-didehydro-3-hydroxy-2,3-dihydrotabersonine + AH2
(3r)-3-hydroxy-2,3-dihydrotabersonine + a <=> (3r)-1,2-didehydro-3-hydroxy-2,3-dihydrotabersonine + ah2