NADH:ubiquinone reductase (non-electrogenic)
| NADH:ubiquinone reductase (non-electrogenic) | |||||||||
|---|---|---|---|---|---|---|---|---|---|
Structure of NADH dehydrogenase (quinone). PDB entry 3iam | |||||||||
| Identifiers | |||||||||
| EC no. | 1.6.5.9 | ||||||||
| CAS no. | 9028-04-0 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| Gene Ontology | AmiGO / QuickGO | ||||||||
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NADH:ubiquinone reductase (non-electrogenic) (EC 1.6.5.9, NDH-2, ubiquinone reductase, coenzyme Q reductase, dihydronicotinamide adenine dinucleotide-coenzyme Q reductase, DPNH-coenzyme Q reductase, DPNH-ubiquinone reductase, NADH-coenzyme Q oxidoreductase, NADH-coenzyme Q reductase, NADH-CoQ oxidoreductase, NADH-CoQ reductase) is an enzyme with systematic name NADH:ubiquinone oxidoreductase. This enzyme catalyses the following chemical reaction:
- NADH + H+ + a quinone NAD+ + a quinol
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).
An important example of this reaction is:
- NADH + H+ + ubiquinone NAD+ + ubiquinol
This enzyme is a flavoprotein (FAD). It 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."
In the electron transport chain NADH is mainly used to create a concentration gradient of hydrogen in order to make ATP. After NADH is oxidized to NAD+, 4 hydrogens are pumped out.