In enzymology, a codeinone reductase (NADPH) (EC 1.1.1.247) is an enzyme that catalyzes the chemical reaction

codeine + NADP⁺ codeinone + NADPH + H⁺

Thus, the two substrates of this enzyme are codeine and NADP⁺, whereas its 3 products are codeinone, NADPH, and H⁺.

This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD⁺ or NADP⁺ as acceptor. The systematic name of this enzyme class is codeine:NADP⁺ oxidoreductase. This enzyme participates in alkaloid biosynthesis i.

• Lenz R; Zenk MH (1995). "Stereoselective reduction of codeinone, the penultimate step during morphine biosynthesis in Papaver somniferum". Tetrahedron Lett. 36 (14): 2449–2452. doi:10.1016/0040-4039(95)00278-K.
• Lenz R, Zenk MH (1995). "Purification and properties of codeinone reductase (NADPH) from Papaver somniferum cell cultures and differentiated plants". Eur. J. Biochem. 233 (1): 132–9. doi:10.1111/j.1432-1033.1995.132_1.x. PMID 7588736.