In enzymology, a tropinone reductase II () is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are pseudotropine and NADP<sup>+</sup>, whereas its 3 products are tropinone, NADPH, and H<sup>+</sup>.
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD<sup>+</sup> or NADP<sup>+</sup> as acceptor. The systematic name of this enzyme class is pseudotropine:NADP<sup>+</sup> 3-oxidoreductase. Other names in common use include tropinone (psi-tropine-forming) reductase, pseudotropine forming tropinone reductase, tropinone reductase (ambiguous), and TR-II. This enzyme participates in alkaloid biosynthesis ii.
As of late 2007, 6 structures have been solved for this class of enzymes, with PDB accession codes , , , , , and .