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EC Number

Catalytic Site Atlas

CSA LITERATURE entry for 1emd

E.C. namemalate dehydrogenase
SpeciesEscherichia coli (Bacteria)
E.C. Number (IntEnz)
CSA Homologues of 1emdThere are 123 Homologs
CSA Entries With UniProtID P61889
CSA Entries With EC Number
PDBe Entry 1emd
PDBSum Entry 1emd
MACiE Entry 1emd

Literature Report

IntroductionMalonate dehydrogenase (MDHase) catalyses the reversible oxidation of malonate to oxaloacetate, a reaction dependent upon the oxidation/reduction of NAD cofactor. The enzyme functions as an important component in the citric acid cycle in the prokaryotic cytoplasm and the malate/aspartate shuttle in eukaryotic cytoplasm.
MechansimThe enzyme catalyses the interconversion of malonate and oxaloacetate with the oxidation and reduction of the NAD cofactor. A histidine-aspartate pair form a proton relay system in the active site, which allows the histidine to act as both a general acid and general base to the substrate. In the direction of reduction, a water molecule acts as the proton donor while in the direction of oxidation the 2-hydroxy group of the substrate acts as the donor.

Catalytic Sites for 1emd

Annotated By Reference To The Literature - Site 1 (Perform Site Search)
ResidueChainNumberUniProtKB NumberFunctional PartFunctionTargetDescription
HisA177177macie:sideChainThe residue acts as a general base towards the 2-hydroyl group of the oxaloacetate in the direction of oxidation, and as a general acid in the direction of reduction. It is involved in a proton relay mechanism with Asp 150.
AspA150150macie:sideChainThe residue acts to relay a proton from a water molecule to the His 195 residue in reduction of oxaloacetate to malate.

Literature References

Hall MD
Crystal structure of a ternary complex of Escherichia coli malate dehydrogenase citrate and NAD at 1.9 A resolution.
J Mol Biol 1993 232 213-222
PubMed: 8331658
Birktoft JJ
The presence of a histidine-aspartic acid pair in the active site of 2-hydroxyacid dehydrogenases. X-ray refinement of cytoplasmic malate dehydrogenase.
J Biol Chem 1983 258 472-482
PubMed: 6848515
Goward CR
Malate dehydrogenase: a model for structure, evolution, and catalysis.
Protein Sci 1994 3 1883-1888
PubMed: 7849603