(E)-4-coumaroyl alcohol + A <=> (E)-4-coumaraldehyde + AH2
(e)-4-coumaroyl alcohol + a <=> (e)-4-coumaraldehyde + ah2
(E)-4-coumaroyl alcohol + A <=> (E)-4-coumaraldehyde + AH2
(e)-4-coumaroyl alcohol + a <=> (e)-4-coumaraldehyde + ah2