IUBMB Enzyme Nomenclature


Accepted name: isocitrate—homoisocitrate dehydrogenase

Reaction: (1) isocitrate + NAD+ = 2-oxoglutarate + CO2 + NADH

(2) (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate + NAD+ = 2-oxoadipate + CO2 + NADH + H+

Other name(s): homoisocitrate—isocitrate dehydrogenase; PH1722

Systematic name: isocitrate(homoisocitrate):NAD+ oxidoreductase (decarboxylating)

Comments: Requires Mn2+ and K+ or NH4+ for activity. Unlike EC, isocitrate dehydrogenase (NAD+) and EC, homoisocitrate dehydrogenase, this enzyme, from Pyrococcus horikoshii, can use both isocitrate and homoisocitrate as substrates. The enzyme may play a role in both the lysine and glutamate biosynthesis pathways.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number:


1. Miyazaki, K. Bifunctional isocitrate-homoisocitrate dehydrogenase: a missing link in the evolution of β-decarboxylating dehydrogenase. Biochem. Biophys. Res. Commun. 331 (2005) 341-346. [PMID: 15845397]

[EC created 2005]

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