Enzyme - 2-dehydro-3-deoxyglucarate aldolase

Alternative Name(s)
  • 2-keto-3-deoxyglucarate aldolase.
  • 2-dehydro-3-deoxy-D-glucarate tartronate-semialdehyde-lyase.
  • Alpha-keto-beta-deoxy-D-glucarate aldolase.

Catalytic Activity

2-dehydro-3-deoxy-D-glucarate = 2-hydroxy-3-oxopropanoate + pyruvate


There are no Cofactors for this Enzyme

Reaction Mechanism

    5-keto-4-deoxy-D-glucarate aldolase GarL is involved in step 2 of the subpathway that synthesizes D-glycerate from galactarate. It catalyses the reversible retro-aldol cleavage of both 5-keto-4-deoxy-D-glucarate and 2-keto-3-deoxy-D-glucarate to pyruvate and tartronic semialdehyde.

    The Asp89-His50 intersubunit dyad deprotonates the metal-bound water molecule. The condensed substrate binds to the metal ion in a bidentate fashion with the C3 carbonyl and C4 hydroxyl interacting with Arg75. The metal-bound hydroxide ion, activated by the intersubunit Asp89-His50 dyad, abstracts the C4 hydroxyl proton, coupled with breakage of the C3−C4 carbon−carbon bond. The resulting aldehyde product and pyruvate enolate are stabilised by the metal ion and Arg74. Protonation of pyruvate enolate at C3 by the Asp89-His50-metal-bound water results in the other product pyruvate, returning the enzyme to the ground state and completing the catalytic cycle.
    Catalytic Residues
    AA Uniprot Uniprot Resid PDB PDB Resid
    Arg P23522 75 1dxe 75
    Glu P23522 153 1dxe 153
    Asp P23522 179 1dxe 179
    His P23522 50 1dxe 50
    Asp P23522 89 1dxe 89
    Step Components

    overall product formed, proton transfer, overall reactant used, bimolecular elimination, native state of enzyme regenerated, assisted keto-enol tautomerisation

    Step 1.

    His50 abstracts a proton from a metal-bound water.

    Step 2.

    The activated water abstracts a proton from the substrate, forming the aldehyde product and the pyruvoyl intermediate.

    Step 3.

    The enolate intermediate collapses with concomitant deprtonation of the water molecule, which in turn abstracts a proton from His50.


    The products of the reaction.

Reaction Parameters

There are no kinetic parameters information for this Enzyme

Associated Proteins

Protein name Organism
5-keto-4-deoxy-D-glucarate aldolase Escherichia coli (strain K12)
2-dehydro-3-deoxyglucarate aldolase Delftia sp. RIT313
GarL protein Jannaschia aquimarina
Alpha-dehydro-beta-deoxy-D-glucarate aldolase Mesorhizobium plurifarium
Putative 2-dehydro-3-deoxyglucarate aldolase Tetrasphaera japonica T1-X7