Isocitrate/isopropylmalate dehydrogenase family
| Isocitrate/isopropylmalate dehydrogenase | |||||||
|---|---|---|---|---|---|---|---|
crystal structure of k230m isocitrate dehydrogenase in complex with alpha-ketoglutarate | |||||||
| Identifiers | |||||||
| Symbol | Iso_dh | ||||||
| Pfam | PF00180 | ||||||
| Pfam clan | CL0270 | ||||||
| InterPro | IPR001804 | ||||||
| PROSITE | PDOC00389 | ||||||
| SCOP2 | 1hex / SCOPe / SUPFAM | ||||||
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In molecular biology, the isocitrate/isopropylmalate dehydrogenase family is a protein family consisting of the evolutionary related enzymes isocitrate dehydrogenase, 3-isopropylmalate dehydrogenase and tartrate dehydrogenase.
Isocitrate dehydrogenase (IDH), is an important enzyme of carbohydrate metabolism which catalyses the oxidative decarboxylation of isocitrate into alpha-ketoglutarate. 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.
3-isopropylmalate dehydrogenase EC 1.1.1.85 (IMDH) catalyses the third step in the biosynthesis of leucine in bacteria and fungi, the oxidative decarboxylation of 3-isopropylmalate into 2-oxo-4-methylvalerate.
Tartrate dehydrogenase EC 1.1.1.93 catalyses the reduction of tartrate to oxaloglycolate.