v5.1.0.3
Glycine data from LIS
Type | Conserved_site |
Description | 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 [ ]. |
Short Name | Histidinol_DH_CS |