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MetaCyc Enzyme: 4-hydroxybutyrate dehydrogenase

Gene: 4hbD Accession Number: G-10251 (MetaCyc)

Species: Clostridium kluyveri

Subunit composition of 4-hydroxybutyrate dehydrogenase = [4hbD]2
         4-hydroxybutyrate dehydrogenase (NAD) = 4hbD

4-hydroxybutyrate dehydrogenase (NAD) activity has been measured in cell extracts of Clostridium kluyveri grown in the presence of either acetate or succinate. Activity was found only in cells grown with succinate, and was 350 nmoles/mg/min for the reduction, and 70 nmoles/mg/min for the oxidation, suggesting that the reaction occurs mostly in the reduction direction (formation of 4-hydroxybutanoate) [Wolff93].

The 4hbD gene, encoding the enzyme, has been cloned and expressed in Escherichia coli [Sohling96]. This enzyme was purified 42-fold under anaerobic conditions to homogeneity, and found to be a homodimer [Wolff95]. The protein contains two atoms of Cu and one atom of Fe per monomeric unit.

Molecular Weight of Polypeptide: 41.756 kD (from nucleotide sequence), 41.6 kD (experimental) [Wolff95]

Molecular Weight of Multimer: 86.0 kD (experimental) [Wolff95]

Unification Links: Protein Model Portal:P38945, String:431943.CKL_3014, UniProt:P38945

Relationship Links: Entrez-Nucleotide:RELATED-TO:L21902, InterPro:IN-FAMILY:IPR001670, InterPro:IN-FAMILY:IPR018211, Pfam:IN-FAMILY:PF00465, Prosite:IN-FAMILY:PS00060

Gene-Reaction Schematic

Gene-Reaction Schematic

Created 18-Oct-2007 by Caspi R, SRI International

Enzymatic reaction of: 4-hydroxybutyrate dehydrogenase

Inferred from experiment

EC Number:

4-hydroxybutanoate + NAD+ ⇄ succinate semialdehyde + NADH + H+

The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the direction in which it was curated.

This reaction is reversible.

In Pathways: succinate fermentation to butanoate

When co-expressed in E. coli with the sucD gene, activity in cell extracts was 475 mU/mg [Sohling96]. The enzyme exhibits maximum activity at pH 6.1 for the reduction of succinic semialdehyde and at pH 9.4 for the oxidization of 4-hydroxybutanoate [Wolff95].

Cofactors or Prosthetic Groups: Cu2+ [Wolff95], Fe3+ [Wolff95]

Inhibitors (Other): oxygen [Wolff95]Kinetic Parameters:
Substrate Km (μM) Citations
NADH 150.0 [Wolff95]
4-hydroxybutanoate 55.0 [Wolff95]
NAD+ 670.0 [Wolff95]
succinate semialdehyde 560.0 [Wolff95]

pH(opt): 6.1 [Wolff95]


Sohling93: Sohling B, Gottschalk G (1993). "Purification and characterization of a coenzyme-A-dependent succinate-semialdehyde dehydrogenase from Clostridium kluyveri." Eur J Biochem 212(1);121-7. PMID: 8444151

Sohling96: Sohling B, Gottschalk G (1996). "Molecular analysis of the anaerobic succinate degradation pathway in Clostridium kluyveri." J Bacteriol 178(3);871-80. PMID: 8550525

Wolff93: Wolff RA, Urben GW, O'Herrin SM, Kenealy WR (1993). "Dehydrogenases involved in the conversion of succinate to 4-hydroxybutanoate by Clostridium kluyveri." Appl Environ Microbiol 59(6);1876-82. PMID: 8328804

Wolff95: Wolff RA, Kenealy WR (1995). "Purification and characterization of the oxygen-sensitive 4-hydroxybutanoate dehydrogenase from Clostridium kluyveri." Protein Expr Purif 6(2);206-12. PMID: 7606170

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Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by Pathway Tools version 19.5 (software by SRI International) on Wed May 4, 2016, biocyc13.