NADH:ubiquinone reductase (non-electrogenic)
NADH:ubiquinone reductase is an enzyme with systematic name NADH:ubiquinone oxidoreductase. This enzyme catalyses the following chemical reaction:
The 3 substrates of this enzyme are NADH, H+, and a quinone, whereas its two products are NAD+ and a quinol.
An important example of this reaction is:
This enzyme is a flavoprotein. 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: oxidoreductase. Other names in common use include reduced nicotinamide adenine dinucleotide dehydrogenase, NADH-quinone oxidoreductase, NADH ubiquinone oxidoreductase, DPNH-menadione reductase, D-diaphorase, and NADH2 dehydrogenase , and mitochondrial 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. 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.