In enzymology, a gluconate 5-dehydrogenase (EC 1.1.1.69) is an enzyme that catalyzes the chemical reaction

D-gluconate + NAD(P)⁺ ${\displaystyle \rightleftharpoons }$ 5-dehydro-D-gluconate + NAD(P)H + H⁺

The 3 substrates of this enzyme are D-gluconate, NAD⁺, and NADP⁺, whereas its 4 products are 5-dehydro-D-gluconate, NADH, 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 D-gluconate:NAD(P)⁺ 5-oxidoreductase. Other names in common use include 5-keto-D-gluconate 5-reductase, 5-keto-D-gluconate 5-reductase, 5-ketogluconate 5-reductase, 5-ketogluconate reductase, and 5-keto-D-gluconate reductase.

As of late 2007, only one structure has been solved for this class of enzymes, with the PDB accession code 1VL8.

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