EC |
1.1.1.41 |
Accepted name: |
isocitrate dehydrogenase (NAD+) |
Reaction: |
isocitrate + NAD+ = 2-oxoglutarate + CO2 + NADH |
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For diagram of the citric-acid cycle, click here |
Glossary: |
isocitrate = (1R,2S)-1-hydroxypropane-1,2,3-tricarboxylate (previously known as threo-Ds-isocitrate) |
Other name(s): |
isocitric dehydrogenase; β-ketoglutaric-isocitric carboxylase; isocitric acid dehydrogenase; NAD dependent isocitrate dehydrogenase; NAD isocitrate dehydrogenase; NAD-linked isocitrate dehydrogenase; NAD-specific isocitrate dehydrogenase; NAD isocitric dehydrogenase; isocitrate dehydrogenase (NAD); IDH (ambiguous); nicotinamide adenine dinucleotide isocitrate dehydrogenase |
Systematic name: |
isocitrate:NAD+ oxidoreductase (decarboxylating) |
Comments: |
Requires Mn2+ or Mg2+ for activity. Unlike EC 1.1.1.42, isocitrate dehydrogenase (NADP+), oxalosuccinate cannot be used as a substrate. In eukaryotes, isocitrate dehydrogenase exists in two forms: an NAD+-linked enzyme found only in mitochondria and displaying allosteric properties, and a non-allosteric, NADP+-linked enzyme that is found in both mitochondria and cytoplasm [7]. The enzyme from some species can also use NADP+ but much more slowly [9]. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9001-58-5 |
References: |
1. |
Hathaway, J.A. and Atkinson, D.E. The effect of adenylic acid on yeast nicotinamide adenine dinucleotide isocitrate dehydrogenase, a possible metabolic control mechanism. J. Biol. Chem. 238 (1963) 2875–2881. [PMID: 14063317] |
2. |
Kornberg, A. and Pricer, W.E. Di- and triphosphopyridine nucleotide isocitric dehydrogenase in yeast. J. Biol. Chem. 189 (1951) 123–136. [PMID: 14832224] |
3. |
Plaut, G.W.E. Isocitrate dehydrogenases. In: Boyer, P.D., Lardy, H. and Myrbäck, K. (Ed.), The Enzymes, 2nd edn, vol. 7, Academic Press, New York, 1963, pp. 105–126. |
4. |
Plaut, G.W.E. and Sung, S.-C. Diphosphopyridine nucleotide isocitric dehydrogenase from animal tissues. J. Biol. Chem. 207 (1954) 305–314. [PMID: 13152105] |
5. |
Ramakrishnan, C.V. and Martin, S.M. Isocitric dehydrogenase in Aspergillus niger. Arch. Biochem. Biophys. 55 (1955) 403–407. |
6. |
Vickery, H.B. A suggested new nomenclature for the isomers of isocitric acid. J. Biol. Chem. 237 (1962) 1739–1741. [PMID: 13925783] |
7. |
Camacho, M.L., Brown, R.A., Bonete, M.J., Danson, M.J. and Hough, D.W. Isocitrate dehydrogenases from Haloferax volcanii and Sulfolobus solfataricus: enzyme purification, characterisation and N-terminal sequence. FEMS Microbiol. Lett. 134 (1995) 85–90. [DOI] [PMID: 8593959] |
8. |
Kim, Y.O., Koh, H.J., Kim, S.H., Jo, S.H., Huh, J.W., Jeong, K.S., Lee, I.J., Song, B.J. and Huh, T.L. Identification and functional characterization of a novel, tissue-specific NAD+-dependent isocitrate dehydrogenase β subunit isoform. J. Biol. Chem. 274 (1999) 36866–36875. [DOI] [PMID: 10601238] |
9. |
Inoue, H., Tamura, T., Ehara, N., Nishito, A., Nakayama, Y., Maekawa, M., Imada, K., Tanaka, H. and Inagaki, K. Biochemical and molecular characterization of the NAD+-dependent isocitrate dehydrogenase from the chemolithotroph Acidithiobacillus thiooxidans. FEMS Microbiol. Lett. 214 (2002) 127–132. [DOI] [PMID: 12204383] |
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[EC 1.1.1.41 created 1961, modified 2005] |
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EC |
1.1.1.42 |
Accepted name: |
isocitrate dehydrogenase (NADP+) |
Reaction: |
isocitrate + NADP+ = 2-oxoglutarate + CO2 + NADPH + H+ (overall reaction) (1a) isocitrate + NADP+ = oxalosuccinate + NADPH + H+ (1b) oxalosuccinate = 2-oxoglutarate + CO2 |
|
For diagram of the citric-acid cycle, click here |
Glossary: |
isocitrate = (1R,2S)-1-hydroxypropane-1,2,3-tricarboxylate (previously known as threo-Ds-isocitrate)
oxalosuccinate = 1-oxopropane-1,2,3-tricarboxylate |
Other name(s): |
oxalosuccinate decarboxylase; oxalsuccinic decarboxylase; isocitrate (NADP) dehydrogenase; isocitrate (nicotinamide adenine dinucleotide phosphate) dehydrogenase; NADP-specific isocitrate dehydrogenase; NADP-linked isocitrate dehydrogenase; NADP-dependent isocitrate dehydrogenase; NADP isocitric dehydrogenase; isocitrate dehydrogenase (NADP-dependent); NADP-dependent isocitric dehydrogenase; triphosphopyridine nucleotide-linked isocitrate dehydrogenase-oxalosuccinate carboxylase; NADP+-linked isocitrate dehydrogenase; IDH (ambiguous); dual-cofactor-specific isocitrate dehydrogenase; NADP+-ICDH; NADP+-IDH; IDP; IDP1; IDP2; IDP3 |
Systematic name: |
isocitrate:NADP+ oxidoreductase (decarboxylating) |
Comments: |
Requires Mn2+ or Mg2+ for activity. Unlike EC 1.1.1.41, isocitrate dehydrogenase (NAD+), oxalosuccinate can be used as a substrate. In eukaryotes, isocitrate dehydrogenase exists in two forms: an NAD+-linked enzyme found only in mitochondria and displaying allosteric properties, and a non-allosteric, NADP+-linked enzyme that is found in both mitochondria and cytoplasm [6]. The enzyme from some species can also use NAD+ but much more slowly [6,7]. |
Links to other databases: |
BRENDA, EXPASY, GTD, KEGG, MetaCyc, PDB, CAS registry number: 9028-48-2 |
References: |
1. |
Agosin, M.U. and Weinbach, E.C. Partial purification and characterization of the isocitric dehydrogenase from Trypanosoma cruzi. Biochim. Biophys. Acta 21 (1956) 117–126. [DOI] [PMID: 13363868] |
2. |
Moyle, J. and Dixon, M. Purification of the isocitrate enzyme (triphosphopyridine nucleotide-linked isocitrate dehydrogenase-oxalosuccinate carboxylase). Biochem. J. 63 (1956) 548–552. [PMID: 13355848] |
3. |
Plaut, G.W.E. Isocitrate dehydrogenases. In: Boyer, P.D., Lardy, H. and Myrbäck, K. (Ed.), The Enzymes, 2nd edn, vol. 7, Academic Press, New York, 1963, pp. 105–126. |
4. |
Siebert, G., Dubuc, J., Warner, R.C. and Plaut, G.W.E. The preparation of isocitrate dehydrogenase from mammalian heart. J. Biol. Chem. 226 (1957) 965–975. [PMID: 13438885] |
5. |
Vickery, H.B. A suggested new nomenclature for the isomers of isocitric acid. J. Biol. Chem. 237 (1962) 1739–1741. [PMID: 13925783] |
6. |
Camacho, M.L., Brown, R.A., Bonete, M.J., Danson, M.J. and Hough, D.W. Isocitrate dehydrogenases from Haloferax volcanii and Sulfolobus solfataricus: enzyme purification, characterisation and N-terminal sequence. FEMS Microbiol. Lett. 134 (1995) 85–90. [DOI] [PMID: 8593959] |
7. |
Steen, I.H., Lien, T. and Birkeland, N.-K. Biochemical and phylogenetic characterization of isocitrate dehydrogenase from a hyperthermophilic archaeon, Archaeoglobus fulgidus. Arch. Microbiol. 168 (1997) 412–420. [PMID: 9325430] |
8. |
Koh, H.J., Lee, S.M., Son, B.G., Lee, S.H., Ryoo, Z.Y., Chang, K.T., Park, J.W., Park, D.C., Song, B.J., Veech, R.L., Song, H. and Huh, T.L. Cytosolic NADP+-dependent isocitrate dehydrogenase plays a key role in lipid metabolism. J. Biol. Chem. 279 (2004) 39968–39974. [DOI] [PMID: 15254034] |
9. |
Ceccarelli, C., Grodsky, N.B., Ariyaratne, N., Colman, R.F. and Bahnson, B.J. Crystal structure of porcine mitochondrial NADP+-dependent isocitrate dehydrogenase complexed with Mn2+ and isocitrate. Insights into the enzyme mechanism. J. Biol. Chem. 277 (2002) 43454–43462. [DOI] [PMID: 12207025] |
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[EC 1.1.1.42 created 1961, modified 2005] |
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EC |
6.4.1.7 |
Accepted name: |
2-oxoglutarate carboxylase |
Reaction: |
ATP + 2-oxoglutarate + HCO3- = ADP + phosphate + oxalosuccinate |
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For diagram of reaction, click here |
Glossary: |
oxalosuccinate = 1-oxopropane-1,2,3-tricarboxylate |
Other name(s): |
oxalosuccinate synthetase; carboxylating factor for ICDH (incorrect); CFI; OGC |
Comments: |
A biotin-containing enzyme that requires Mg2+ for activity. It was originally thought [1] that this enzyme was a promoting factor for the carboxylation of 2-oxoglutarate by EC 1.1.1.41, isocitrate dehydrogenase (NAD+), but this has since been disproved [2]. The product of the reaction is unstable and is quickly converted into isocitrate by the action of EC 1.1.1.41 [2]. |
Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 60382-75-4 |
References: |
1. |
Aoshima, M., Ishii, M. and Igarashi, Y. A novel biotin protein required for reductive carboxylation of 2-oxoglutarate by isocitrate dehydrogenase in Hydrogenobacter thermophilus TK-6. Mol. Microbiol. 51 (2004) 791–798. [DOI] [PMID: 14731279] |
2. |
Aoshima, M. and Igarashi, Y. A novel oxalosuccinate-forming enzyme involved in the reductive carboxylation of 2-oxoglutarate in Hydrogenobacter thermophilus TK-6. Mol. Microbiol. 62 (2006) 748–759. [DOI] [PMID: 17076668] |
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[EC 6.4.1.7 created 2006] |
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