Reaction: galactarate = (2R,3S)-2,3-dihydroxy-5-oxohexanedioate + H2O
Glossary: galactarate = (2R,3S,4R,5S)-2,3,4,5-tetrahydroxyhexanedioate
(2R,3S)-2,3-dihydroxy-5-oxohexanedioate = 3-deoxy-L-threo-hex-2-ulosarate
Other name(s): D-galactarate hydro-lyase; D-galactarate hydro-lyase (5-dehydro-4-deoxy-D-glucarate-forming); talrD (gene name)/galrD (gene name)
Systematic name: galactarate hydro-lyase (5-dehydro-4-deoxy-D-glucarate-forming)
Comments: The enzyme from the bacterium Escherichia coli is specific for galactarate [2], while the enzyme from Salmonella typhimurium also has activity with L-talarate (cf. EC 4.2.1.156, L-talarate dehydratase) [3]. cf. EC 4.2.1.158, galactarate dehydratase (D-threo-forming).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 37290-78-1
References:
1. Blumenthal, H.J. and Jepson, T. Galactarate dehydrase. Methods Enzymol. 9 (1966) 665-669.
2. Hubbard, B.K., Koch, M., Palmer, D.R., Babbitt, P.C. and Gerlt, J.A. Evolution of enzymatic activities in the enolase superfamily: characterization of the (D)-glucarate/galactarate catabolic pathway in Escherichia coli. Biochemistry 37 (1998) 14369-14375. [PMID: 9772162]
3. Yew, W.S., Fedorov, A.A., Fedorov, E.V., Almo, S.C. and Gerlt, J.A. Evolution of enzymatic activities in the enolase superfamily: L-talarate/galactarate dehydratase from Salmonella typhimurium LT2. Biochemistry 46 (2007) 9564-9577. [PMID: 17649980]
4. Rakus, J.F., Kalyanaraman, C., Fedorov, A.A., Fedorov, E.V., Mills-Groninger, F.P., Toro, R., Bonanno, J., Bain, K., Sauder, J.M., Burley, S.K., Almo, S.C., Jacobson, M.P. and Gerlt, J.A. Computation-facilitated assignment of the function in the enolase superfamily: a regiochemically distinct galactarate dehydratase from Oceanobacillus iheyensis. Biochemistry 48 (2009) 11546-11558. [PMID: 19883118]