Reaction: 1,5-anhydro-D-mannitol + NADP+ = 1,5-anhydro-D-fructose + NADPH + H+
For diagram click here.
Other name(s): 1,5-anhydro-D-fructose reductase (ambiguous); AFR (ambiguous)
Systematic name: 1,5-anhydro-D-mannitol:NADP+ oxidoreductase
Comments: This enzyme is present in some but not all Rhizobium species and belongs in the GFO/IDH/MocA protein family [2]. This enzyme differs from hepatic 1,5-anhydro-D-fructose reductase, which yields 1,5-anhydro-D-glucitol as the product (see EC 1.1.1.263). In Sinorhizobium morelense, the product of the reaction, 1,5-anhydro-D-mannitol, can be further metabolized to D-mannose [1]. The enzyme also reduces 1,5-anhydro-D-erythro-hexo-2,3-diulose and 2-ketoaldoses (called osones), such as D-glucosone (D-arabino-hexos-2-ulose) and 6-deoxy-D-glucosone. It does not reduce common aldoses and ketoses, or non-sugar aldehydes and ketones [1].
Links to other databases: BRENDA, EAWAG-BBD, EXPASY, KEGG, Metacyc, PDB, CAS registry number:
References:
1. Kühn, A., Yu, S. and Giffhorn, F. Catabolism of 1,5-anhydro-D-fructose in Sinorhizobium morelense S-30.7.5: discovery, characterization, and overexpression of a new 1,5-anhydro-D-fructose reductase and its application in sugar analysis and rare sugar synthesis. Appl. Environ. Microbiol. 72 (2006) 1248-1257. [PMID: 16461673]
2. Dambe, T.R., Kühn, A.M., Brossette, T., Giffhorn, F. and Scheidig, A.J. Crystal structure of NADP(H)-dependent 1,5-anhydro-D-fructose reductase from Sinorhizobium morelense at 2.2 Å resolution: construction of a NADH-accepting mutant and its application in rare sugar synthesis. Biochemistry 45 (2006) 10030-10042. [PMID: 16906761]