MetaCyc Reaction:

Superclasses: Reactions Classified By Conversion TypeSimple ReactionsChemical Reactions
Reactions Classified By SubstrateSmall-Molecule Reactions

EC Number:

Enzymes and Genes:

Haloferax mediterranei: (D)-2-hydroxyacid dehydrogenase (NADP+)Inferred from experiment: ddh

The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the Enzyme Commission system.

Most BioCyc compounds have been protonated to a reference pH value of 7.3. Please see the PGDB Concepts Guide for more information.

Mass balance status: Balanced.

Instance reaction:
(R)-2-hydroxybutanoate + NADP+ = 2-oxobutanoate + NADPH + H+ (

Enzyme Commission Primary Name: D-2-hydroxyacid dehydrogenase (NADP+)

Enzyme Commission Synonyms: ddh (gene name)

Standard Gibbs Free Energy (ΔrG in kcal/mol): 22.835754Inferred by computational analysis [Latendresse13]

Enzyme Commission Summary:
This enzyme, characterized from the halophilic archaeon Haloferax mediterranei, catalyses a reversible stereospecific reduction of 2-ketocarboxylic acids into the corresponding D-2-hydroxycarboxylic acids. The enzyme prefers substrates with a main chain of 5 carbons (such as 4-methyl-2-oxopentanoate) to those with a shorter chain, and can use NADH with much lower efficiency. cf. EC, (D)-2-hydroxyacid dehydrogenase (NAD+).

Citations: [Domenech06 ]

Gene-Reaction Schematic

Gene-Reaction Schematic

Instance reaction of [an (R)-2-hydroxycarboxylate + NADP+ = a 2-oxo carboxylate + NADPH + H+] (
i1: (R)-2-hydroxybutanoate + NADP+ = 2-oxobutanoate + NADPH + H+ (

Relationship Links: BRENDA:EC:, ENZYME:EC:, IUBMB-ExplorEnz:EC:

Revised 17-Sep-2012 by Caspi R, SRI International


Domenech06: Domenech J, Ferrer J (2006). "A new D-2-hydroxyacid dehydrogenase with dual coenzyme-specificity from Haloferax mediterranei, sequence analysis and heterologous overexpression." Biochim Biophys Acta 1760(11);1667-74. PMID: 17049749

Latendresse13: Latendresse M. (2013). "Computing Gibbs Free Energy of Compounds and Reactions in MetaCyc."

Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
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