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 . It is used in the commercial microbial production of ascorbate. cf. EC 18.104.22.1684, 2,5-didehydrogluconate reductase (2-dehydro-D-gluconate-forming).
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, 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]