NADH dehydrogenase (quinone)

In enzymology, a NADH dehydrogenase (quinone) (EC 1.6.5.11) is an enzyme that catalyzes the chemical reaction

NADH + H+ + a quinone NAD+ + a quinol
NADH dehydrogenase (quinone)
Structure of NADH dehydrogenase (quinone). PDB entry 3iam[1]
Identifiers
EC number1.6.99.5
CAS number37256-36-3
Databases
IntEnzIntEnz view
BRENDABRENDA entry
ExPASyNiceZyme view
KEGGKEGG entry
MetaCycmetabolic pathway
PRIAMprofile
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO

The 3 substrates of this enzyme are NADH, H+, and a quinone (electron acceptor), whereas its two products are NAD+ and a quinol (reduced acceptor).

This enzyme belongs to the family of oxidoreductases, specifically those acting on NADH or NADPH with other acceptors. The systematic name of this enzyme class is NADH:(quinone-acceptor) oxidoreductase. Other names in common use include reduced nicotinamide adenine dinucleotide (quinone) dehydrogenase, NADH-quinone oxidoreductase, NADH ubiquinone oxidoreductase, DPNH-menadione reductase, D-diaphorase, and NADH2 dehydrogenase (quinone), and mitochondrial (mt) complex I. This enzyme participates in oxidative phosphorylation. Several compounds are known to inhibit this enzyme, including AMP, and 2,4-dinitrophenol. NADH dehydrogenase is involved in the first step of the electron transport chain of oxidative phosphorylation (OXPHOS). Any change in the electron transport component caused by a mutation might effect the normal electron flow. This might be leading "an increase of bifurcation and generation of superoxidase radicals and increase oxidative stress in various types of cancer cells."[2]

In the electron transport chain NADH is mainly used to create a concentration gradient of hydrogen in order to make ATP. Since After NADH is oxidized a hydrogen is pumped out and NAD+ will be a product.[3]

Structural studies

Several structures are available of this enzyme, which is part of the respiratory chain. It is a multi-subunit enzyme in which this activity is located in the hydrophilic domain. The subunits of the membrane-embedded domain are responsible for proton translocation.

References
  1. Berrisford JM, Sazanov LA (2009). "Structural basis for the mechanism of respiratory complex I". J Biol Chem. 284 (43): 29773–83. doi:10.1074/jbc.M109.032144. PMC 2785608. PMID 19635800.
  2. Yusnita, Yakob; Norsiah, Md Desa; Rahman, A. Jamal (2010-12-01). "Mutations in mitochondrial NADH dehydrogenase subunit 1 (mtND1) gene in colorectal carcinoma". The Malaysian Journal of Pathology. 32 (2): 103–110. ISSN 0126-8635. PMID 21329181.
  3. Alberts, Bruce; Johnson, Alexander; Lewis, Julian; Raff, Martin; Roberts, Keith; Walter, Peter (2002-01-01). "Electron-Transport Chains and Their Proton Pumps". Cite journal requires |journal= (help)
  • Koli AK, Yearby C, Scott W, Donaldson KO (1969). "Purification and properties of three separate menadione reductases from hog liver". J. Biol. Chem. 244 (4): 621–9. PMID 4388793.


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