ExplorEnz: EC 4.2.1.42

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4.2.1.42

Accepted name:

galactarate dehydratase

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); galactarate dehydratase (L-threo-forming)

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, Gene, 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. [DOI] [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. [DOI] [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. [DOI] [PMID: 19883118]

[EC 4.2.1.42 created 1972, modified 2015]