In enzymology, a testosterone 17beta-dehydrogenase is an enzyme that catalyzes the chemical reaction between testosterone and androst-4-ene-3,17-dione. 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 17beta-hydroxysteroid:NAD⁺ 17-oxidoreductase. Other names in common use include 17-ketoreductase and 17beta-HSD. This enzyme participates in androgen and estrogen metabolism.

There are two variants of the enzyme, one that uses NAD⁺ as a substrate, and one that uses NADP⁺ as acceptor.

This variant of testosterone 17beta-dehydrogenase (EC 1.1.1.239) catalyzes the reaction

testosterone + NAD⁺ ${\displaystyle \rightleftharpoons }$ androst-4-ene-3,17-dione + NADH + H⁺

Thus, the two substrates of this enzyme are testosterone and NAD⁺, whereas its 3 products are androst-4-ene-3,17-dione, NADH, and H⁺.

This variant of testosterone 17beta-dehydrogenase (EC 1.1.1.64) catalyzes the reaction

testosterone + NADP⁺ ${\displaystyle \rightleftharpoons }$ androst-4-ene-3,17-dione + NADPH + H⁺

Thus, the two substrates of this enzyme are testosterone and NADP⁺, whereas its 3 products are androst-4-ene-3,17-dione, NADPH, and H⁺.

• Testosterone glucuronide

• Endahl GL, Kochakian CD, Hamm D (1960). "Separation of a Triphosphopyridine Nucleotide-specific from a Diphosphopyridine Nucleotide-specific 17β-Hydroxy-(testosterone)dehydrogenase of Guinea Pig Liver". J. Biol. Chem. 235 (10): 2792–6. doi:10.1016/S0021-9258(18)64542-9. PMID 13696735.
• Sweat ML, Samuels LT, Lumry R (1950). "Preparation and characterization of the enzyme which converts testosterone to androstenedione". J. Biol. Chem. 185 (1): 75–84. doi:10.1016/S0021-9258(18)56395-X. PMID 15436478.
• Villee CA; Spencer JM (1960). "Some Properties of the Pyridine Nucleotide-specific 17β-Hydroxy Steroid Dehydrogenases of Guinea Pig Liver". J. Biol. Chem. 235 (12): 3615–3619. doi:10.1016/S0021-9258(18)64518-1. PMID 13781425.

• Testosterone Enhancement