| Description | This entry represents a structural domain found in aldehyde dehydrogenases [ ] and histidinol dehydrogenases []. These proteins contain two similar domains, each with a 3-layer α/β/α structure, which probably arose from a duplication. These enzymes bind NAD differently from other NAD(P)-dependent oxidoreductases.Aldehyde dehydrogenases ( and ) are enzymes that oxidize a wide variety of aliphatic and aromatic aldehydes using NADP as a cofactor. In mammals at least four different forms of the enzyme are known [ ]: class-1 (or Ald C) a tetrameric cytosolic enzyme, class-2 (or Ald M) a tetrameric mitochondrial enzyme, class- 3 (or Ald D) a dimeric cytosolic enzyme, and class IV a microsomal enzyme. Aldehyde dehydrogenases have also been sequenced from fungal and bacterial species. A number of enzymes are known to be evolutionary related to aldehyde dehydrogenases. A glutamic acid and a cysteine residue have been implicated in the catalytic activity of mammalian aldehyde dehydrogenase. Histidinol dehydrogenase ( ) (HDH) catalyses the terminal step in the biosynthesis of histidine in bacteria, fungi, and plants, the four-electron oxidation of L-histidinol to histidine. In 4-electron dehydrogenases, a single active site catalyses 2 separate oxidation steps: oxidation of the substrate alcohol to an intermediate aldehyde; and oxidation of the aldehyde to the product acid, in this case His [ ]. The reaction proceeds via a tightly- or covalently-bound inter-mediate, and requires the presence of 2 NAD molecules []. By contrast with most dehydrogenases, the substrate is bound before the NAD coenzyme []. A Cys residue has been implicated in the catalytic mechanism of the second oxidative step []. In bacteria HDH is a single chain polypeptide; in fungi it is the C-terminal domain of a multifunctional enzyme which catalyzes three different steps of histidine biosynthesis; and in plants it is expressed as nuclear encoded protein precursor which is exported to the chloroplast [].This entry also includes Retinal dehydrogenase 2 that share similar active site. This enzyme catalyses the NAD-dependent oxidation of aldehyde substrates, such as all-trans-retinal and all-trans-13,14-dihydroretinal, to their corresponding carboxylic acids, all-trans-retinoate and all-trans-13,14-dihydroretinoate, respectively [ , ]. It lacks activity with benzaldehyde, acetaldehyde and octanal []. | Name | Aldehyde/histidinol dehydrogenase |
| Short Name | Ald_DH/histidinol_DH | Type | Homologous_superfamily |
Powered by
Have you tried our InterMine mobile apps?
and interoperation is funded by 
