Isocitrate dehydrogenase (NAD+) explained

Isocitrate dehydrogenase (NAD+)
Ec Number:	1.1.1.41
Cas Number:	9001-58-5
Width:	270

Isocitrate dehydrogenase (NAD+) (isocitric dehydrogenase, beta-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) is an enzyme with systematic name isocitrate:NAD+ oxidoreductase (decarboxylating).^{[1] [2] [3] [4] [5] [6] [7]} This enzyme catalyses the following chemical reaction

isocitrate + NAD⁺

\rightleftharpoons 2-oxoglutarate + CO₂ + NADH

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. The enzyme from some species can also use NADP⁺ but much more slowly.^{[8] [9]}

Notes and References

1. Hathaway JA, Atkinson DE . The effect of adenylic acid on yeast nicotinamide adenine dinucleotide isocitrate dehydrogenase, a possible metabolic control mechanism . The Journal of Biological Chemistry . 238 . 2875–81 . August 1963 . 14063317 .
2. Kornberg A, Pricer WE . Di- and triphosphopyridine nucleotide isocitric dehydrogenases in yeast . The Journal of Biological Chemistry . 189 . 1 . 123–36 . March 1951 . 14832224 .
3. Book: Isocitrate dehydrogenases . The Enzymes . Plaut GW, Lardy H, Myrbäck K . 1963 . 7 . 105–126 . Boyer PD . 2nd . Academic Press . New York .
4. Plaut GW, Sung SC . Diphosphopyridine nucleotide isocitric dehydrogenase from animal tissues . The Journal of Biological Chemistry . 207 . 1 . 305–14 . March 1954 . 13152105 .
5. Isocitric dehydrogenase in Aspergillus niger . Ramakrishnan CV, Martin SM . Arch. Biochem. Biophys. . 1955 . 55 . 403–407 . 10.1016/0003-9861(55)90421-5.
6. Vickery HB . A suggested new nomenclature for the isomers of isocitric acid . The Journal of Biological Chemistry . 237 . 1739–41 . June 1962 . 13925783 .
7. Camacho ML, Brown RA, Bonete MJ, Danson MJ, Hough DW . Isocitrate dehydrogenases from Haloferax volcanii and Sulfolobus solfataricus: enzyme purification, characterisation and N-terminal sequence . FEMS Microbiology Letters . 134 . 1 . 85–90 . December 1995 . 8593959 . 10.1016/0378-1097(95)00388-l . free .
8. Kim YO, Koh HJ, Kim SH, Jo SH, Huh JW, Jeong KS, Lee IJ, Song BJ, Huh TL . Identification and functional characterization of a novel, tissue-specific NAD(+)-dependent isocitrate dehydrogenase beta subunit isoform . The Journal of Biological Chemistry . 274 . 52 . 36866–75 . December 1999 . 10601238 . 10.1074/jbc.274.52.36866 . free .
9. Inoue H, Tamura T, Ehara N, Nishito A, Nakayama Y, Maekawa M, Imada K, Tanaka H, Inagaki K . Biochemical and molecular characterization of the NAD(+)-dependent isocitrate dehydrogenase from the chemolithotroph Acidithiobacillus thiooxidans . FEMS Microbiology Letters . 214 . 1 . 127–32 . August 2002 . 12204383 . 10.1016/s0378-1097(02)00857-1 . free .