In enzymology, homoisocitrate dehydrogenase () is an enzyme that catalyzes the chemical reaction
The two substrates of this enzyme are (-)-homoisocitric acid and oxidised nicotinamide adenine dinucleotide (NAD<sup>+</sup>). Its products are 2-oxoadipic acid, carbon dioxide, reduced NADH, and a proton.
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD<sup>+</sup> or NADP<sup>+</sup> as acceptor. The systematic name of this enzyme class is (1R,2S)-1-hydroxybutane-1,2,4-tricarboxylate:NAD<sup>+</sup> oxidoreductase (decarboxylating). Other names in common use include 2-hydroxy-3-carboxyadipate dehydrogenase, 3-carboxy-2-hydroxyadipate dehydrogenase, homoisocitric dehydrogenase, (âÂÂ)-1-hydroxy-1,2,4-butanetricarboxylate:NAD<sup>+</sup> oxidoreductase, (decarboxylating), 3-carboxy-2-hydroxyadipate:NAD<sup>+</sup> oxidoreductase (decarboxylating), and HICDH. This enzyme participates in lysine biosynthesis.
As of late 2007, only one structure has been solved for this class of enzymes, with the PDB accession code .