Histidinol dehydrogenase, monofunctional (IPR022695)
Short name: Histidinol_DH_monofunct
Overlapping homologous superfamilies
- Aldehyde/histidinol dehydrogenase (IPR016161)
- Histidinol dehydrogenase (IPR012131)
- Histidinol dehydrogenase, monofunctional (IPR022695)
Histidinol dehydrogenase (HDH) catalyzes 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 [PMID: 3533140]. The reaction proceeds via a tightly- or covalently-bound inter-mediate, and requires the presence of 2 NAD molecules [PMID: 3533140]. By contrast with most dehydrogenases, the substrate is bound before the NAD coenzyme [PMID: 3533140]. A Cys residue has been implicated in the catalytic mechanism of the second oxidative step [PMID: 3533140].
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 [PMID: 2034659].
This entry represents histidinol dehydrogenase EC:184.108.40.206.
- PIRSF000099 (Histidinol_dh)