IUBMB Enzyme Nomenclature


Accepted name: 2,5-didehydrogluconate reductase (2-dehydro-L-gulonate-forming)

Reaction: 2-dehydro-L-gulonate + NADP+ = 2,5-didehydro-D-gluconate + NADPH + H+

Glossary: 2-dehydro-L-gulonate = 2-dehydro-L-idonate = 2-keto-L-gulonate

Other name(s): 2,5-diketo-D-gluconate-reductase (ambiguous); YqhE reductase; dkgA (gene name); dkgB (gene name)

Systematic name: 2-dehydro-D-gluconate:NADP+ 2-oxidoreductase (2-dehydro-L-gulonate-forming)

Comments: The enzyme is involved in ketogluconate metabolism, and catalyses the reaction in vivo in the reverse direction to that shown [1]. It is used in the commercial microbial production of ascorbate. cf. EC, 2,5-didehydrogluconate reductase (2-dehydro-D-gluconate-forming).

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number:


1. Sonoyama, T. and Kobayashi, K. Purification and properties of two 2,5-diketo-D-gluconate reductases from a mutant strain derived from Corynebacterium sp. J Ferment Technol. 65 (1987) 311-317.

2. Miller, J.V., Estell, D.A. and Lazarus, R.A. Purification and characterization of 2,5-diketo-D-gluconate reductase from Corynebacterium sp. J. Biol. Chem. 262 (1987) 9016-9020. [PMID: 3597405]

3. Yum, D.Y., Lee, B.Y. and Pan, J.G. Identification of the yqhE and yafB genes encoding two 2,5-diketo-D-gluconate reductases in Escherichia coli. Appl. Environ. Microbiol. 65 (1999) 3341-3346. [PMID: 10427017]

4. Maremonti, M., Greco, G. and Wichmann, R. Characterisation of 2,5-diketo-D-gluconic acid reductase from Corynebacterium sp. Biotechnology Letters 18 (1996) 845-850.

5. Khurana, S., Powers, D.B., Anderson, S. and Blaber, M. Crystal structure of 2,5-diketo-D-gluconic acid reductase A complexed with NADPH at 2.1-Å resolution. Proc. Natl. Acad. Sci. USA 95 (1998) 6768-6773. [PMID: 9618487]

[EC created 2013]

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