MetaCyc Enzyme: glutamate dehydrogenase (NAD-dependent)

Gene: gdhA Accession Number: G-8963 (MetaCyc)

Species: Halobacterium salinarum

Subunit composition of glutamate dehydrogenase (NAD-dependent) = [GdhA]6
         NAD-glutamate dehydrogenase subunit = GdhA

Halobacterium salinarum is one of the organisms reported to have more than one form of GDH, with different forms utilizing different cofactors (NAD and NADP) [Bonete89, Bonete90]. It was eventually shown that the organism has four genes encoding four different glutamate dehydrogenase enzymes [Ingoldsby05]. Two of these gene products have been purified and characterized biochemically [Bonete96, PerezPomares99]. One of the genes, gdhA1, which was originally predicted to encode an NADP-specific form [Benachenhou91], was found to encode an NAD-specific enzyme, suggesting that sequence information alone in not sufficient to predict the cofator specificity of GDH [Ingoldsby05].

Molecular Weight of Polypeptide: 59.0 kD (experimental) [PerezPomares99 ]

Relationship Links: Entrez-Nucleotide:PART-OF:X63837

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

Enzymatic reaction of: glutamate dehydrogenase (NAD-dependent)

Synonyms: glutamic dehydrogenase, L-glutamate:NAD+ oxidoreductase (deaminating)

EC Number:

L-glutamate + NAD+ + H2O <=> 2-oxoglutarate + ammonium + NADH + H+

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction of enzyme catalysis.

This reaction is reversible.

In Pathways: L-glutamate degradation I

Activators (Unknown Mechanism): L-glutamine [Bonete96] , L-asparagine [Bonete96] , L-aspartate [Bonete96] , L-histidine [Bonete96] , L-arginine [Bonete96] , L-lysine [Bonete96] , L-phenylalanine [Bonete96] , L-tyrosine [Bonete96] , L-tryptophan [Bonete96] , L-cysteine [Bonete96] , L-methionine [Bonete96] , L-threonine [Bonete96] , L-serine [Bonete96] , L-isoleucine [Bonete96] , L-leucine [Bonete96] , L-valine [Bonete96] , L-alanine [Bonete96] , glycine [Bonete96]

Inhibitors (Competitive): NADH [Bonete89, Comment 1] , glutarate [Bonete89, Comment 2] , hydroxylamine [Bonete89, Comment 3] , adipate [Bonete89, Comment 2]

Inhibitors (Noncompetitive): NADP+ [Bonete96, Comment 4] , oxaloacetate [Bonete96, Comment 5] , succinate [Bonete96, Comment 6] , (S)-malate [Bonete96, Comment 7] , fumarate [Bonete96, Comment 8] , L-glutamate [Bonete89, Comment 9]

Inhibitors (Unknown Mechanism): 2-oxoglutarate [Bonete96]

Primary Physiological Regulators of Enzyme Activity: 2-oxoglutarate , L-glutamate , NADH , glutarate , hydroxylamine , adipate


Benachenhou91: Benachenhou N, Baldacci G (1991). "The gene for a halophilic glutamate dehydrogenase: sequence, transcription analysis and phylogenetic implications." Mol Gen Genet 230(3);345-52. PMID: 1766432

Bonete89: Bonete MJ, Camacho ML, Cadenas E (1989). "Kinetic mechanism of Halobacterium halobium NAD+-glutamate dehydrogenase." Biochim Biophys Acta 1989;990(2);150-5. PMID: 2917175

Bonete90: Bonete MJ, Camacho ML, Cadenas E (1990). "Analysis of the kinetic mechanism of halophilic NADP-dependent glutamate dehydrogenase." Biochim Biophys Acta 1990;1041(3);305-10. PMID: 1980084

Bonete96: Bonete MJ, Perez-Pomares F, Ferrer J, Camacho ML (1996). "NAD-glutamate dehydrogenase from Halobacterium halobium: inhibition and activation by TCA intermediates and amino acids." Biochim Biophys Acta 1996;1289(1);14-24. PMID: 8605224

Ingoldsby05: Ingoldsby LM, Geoghegan KF, Hayden BM, Engel PC (2005). "The discovery of four distinct glutamate dehydrogenase genes in a strain of Halobacterium salinarum." Gene 349;237-44. PMID: 15780999

PerezPomares99: Perez-Pomares F, Ferrer J, Camacho M, Pire C, LLorca F, Bonete MJ (1999). "Amino acid residues involved in the catalytic mechanism of NAD-dependent glutamate dehydrogenase from Halobacterium salinarum." Biochim Biophys Acta 1999;1426(3);513-25. PMID: 10076069

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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
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