The isocitrate and isopropylmalate dehydrogenases family includes isocitrate dehydrogenase (IDH), 3-isopropylmalate dehydrogenase (IMDH) and tartrate dehydrogenase.

IDH is an important enzyme of carbohydrate metabolism which catalyses the oxidative decarboxylation of isocitrate into alpha-ketoglutarate [ PUBMED:2682654 … expand

The isocitrate and isopropylmalate dehydrogenases family includes isocitrate dehydrogenase (IDH), 3-isopropylmalate dehydrogenase (IMDH) and tartrate dehydrogenase.

IDH is an important enzyme of carbohydrate metabolism which catalyses the oxidative decarboxylation of isocitrate into alpha-ketoglutarate [ PUBMED:2682654 PUBMED:1939242 ]. IDH is either dependent on NAD ⁺ ( EC:1.1.1.41 ) or on NADP ⁺ ( EC:1.1.1.42 ). In eukaryotes there are at least three isozymes of IDH: two are located in the mitochondrial matrix (one NAD ⁺ -dependent, the other NADP ⁺ -dependent), while the third one (also NADP ⁺ -dependent) is cytoplasmic. In Escherichia coli, the activity of a NADP ⁺ -dependent form of the enzyme is controlled by the phosphorylation of a serine residue; the phosphorylated form of IDH is completely inactivated.

IMDH ( EC:1.1.1.85 ) catalyses the third step in the biosynthesis of leucine in bacteria and fungi, the oxidative decarboxylation of 3-isopropylmalate into 2-oxo-4-methylvalerate [ PUBMED:1748999 PUBMED:7773180 ].

This entry represents a structural domain found in all types of isocitrate dehydrogenase, and in isopropylmalate dehydrogenase and tartrate dehydrogenase. The crystal structure of Escherichia coli isopropylmalate dehydrogenase has been described [ PUBMED:9086278 ].