Retinol Dehydrogenase 16 (RDH16)

Recombinant RoDH-4, expressed in microsomes of Sf9 insect cells using BacoluGold Baculovirus system, oxidizes all-trans-retinol and 13-cis-retinol to corresponding aldehydes and oxidizes the 3alpha-hydroxysteroids androstane-diol and androsterone to dihydrotestosterone and androstanedione, respectively. All-trans-retinol and 13-cis-retinol inhibit RoDH-4 catalyzed oxidation of androsterone with apparent Ki values of 5.8 and 3.5 microM, respectively. All-trans-retinol bound to cellular retinol-binding protein (type I) exhibits a similar Ki value of 3.6 microM. Citral and acyclic isoprenoids also act as inhibitors of RoDH-4 activity. Ethanol is not inhibitory. RoDH-4 can potentially contribute to the biosynthesis of two powerful modulators of gene expression: retinoic acid from retinol and dihydrotestosterone from 3alpha-androstane-diol.