In enzymology, all-trans-retinol 13,14-reductase () is an enzyme, encoded by the RETSAT gene, that catalyzes the chemical reaction
The enzyme acts on retinol (vitamin A) to reduce it to 13,14-dihydroretinol. Its is not known to be able to catalyze reaction in the opposite direction.
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-CH group of donor with other acceptors. The systematic name of this enzyme class is all-trans-13,14-dihydroretinol:acceptor 13,14-oxidoreductase. Other names in common use include retinol saturase, RetSat, (13,14)-all-trans-retinol saturase, and all-trans-retinol:all-trans-13,14-dihydroretinol saturase.
The gene has also been called PPAR-alpha-regulated and starvation-induced gene protein.