Page last updated: 2024-10-24

mitochondrial electron transport, NADH to ubiquinone

Definition

Target type: biologicalprocess

The transfer of electrons from NADH to ubiquinone that occurs during oxidative phosphorylation. [ISBN:0716731363]

Mitochondrial electron transport is a fundamental process that powers cellular respiration, converting energy from food molecules into a usable form called ATP. The NADH to ubiquinone segment of this process involves the transfer of electrons from NADH, a reduced electron carrier, to ubiquinone (Q), a mobile electron carrier in the mitochondrial inner membrane. This process occurs through a series of protein complexes embedded in the membrane, known as Complexes I, II, and III.

Complex I, also known as NADH dehydrogenase, is the primary entry point for electrons from NADH. It binds NADH and uses the energy released during its oxidation to pump protons across the inner mitochondrial membrane, contributing to the proton gradient that drives ATP synthesis. These electrons are then transferred to ubiquinone (Q), reducing it to ubiquinol (QH2).

Complex II, also known as succinate dehydrogenase, is another entry point for electrons, specifically from succinate, a molecule involved in the citric acid cycle. Unlike Complex I, Complex II does not pump protons across the membrane. The electrons from succinate are transferred to ubiquinone, reducing it to ubiquinol.

Ubiquinol, now carrying the electrons from both Complex I and Complex II, moves freely within the membrane. It encounters Complex III, also known as cytochrome bc1 complex. Complex III accepts the electrons from ubiquinol, transferring them to cytochrome c, another mobile electron carrier. During this transfer, Complex III also pumps protons across the membrane, further contributing to the proton gradient.

The overall process of NADH to ubiquinone electron transfer is a key step in mitochondrial respiration. It involves a series of redox reactions, where electrons are transferred from one molecule to another, releasing energy that is used to pump protons across the membrane. This proton gradient is essential for ATP synthesis, the primary energy currency of cells.

The transfer of electrons from NADH to ubiquinone is tightly regulated and is subject to various factors such as the availability of oxygen, the levels of NADH and ubiquinone, and the activity of enzymes involved in the process.

This intricate series of events demonstrates the complexity and precision of cellular respiration, highlighting the crucial role of electron transport in maintaining cellular function and energy production.'
"

Proteins (44)

ProteinDefinitionTaxonomy
Acyl carrier protein, mitochondrialAn acyl carrier protein, mitochondrial that is encoded in the genome of cow. [OMA:P52505, PRO:DNx]Bos taurus (cattle)
NADH dehydrogenase [ubiquinone] flavoprotein 1, mitochondrialAn NADH dehydrogenase [ubiquinone] flavoprotein 1, mitochondrial that is encoded in the genome of cow. [OMA:P25708, PRO:DNx]Bos taurus (cattle)
NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 9An NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 9 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q9Y6M9]Homo sapiens (human)
Complex I intermediate-associated protein 30, mitochondrialA complex I intermediate-associated protein 30, mitochondrial that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q9Y375]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 9, mitochondrialAn NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 9, mitochondrial that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 5An NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 5 that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 6An NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 6 that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] flavoprotein 3, mitochondrialAn NADH dehydrogenase [ubiquinone] flavoprotein 3, mitochondrial that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 8An NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 8 that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] flavoprotein 1, mitochondrialAn NADH dehydrogenase [ubiquinone] flavoprotein 1, mitochondrial that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH-ubiquinone oxidoreductase 75 kDa subunit, mitochondrialAn NADH-ubiquinone oxidoreductase 75 kDa subunit, mitochondrial that is encoded in the genome of human. [PRO:DNx, UniProtKB:P28331]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] flavoprotein 2, mitochondrialAn NADH dehydrogenase [ubiquinone] flavoprotein 2, mitochondrial that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 7An NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 7 that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH-ubiquinone oxidoreductase chain 6An NADH-ubiquinone oxidoreductase chain 6 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P03923]Homo sapiens (human)
NADH-ubiquinone oxidoreductase chain 5An NADH-ubiquinone oxidoreductase chain 5 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P03915]Homo sapiens (human)
NADH-ubiquinone oxidoreductase chain 4An NADH-ubiquinone oxidoreductase chain 4 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P03905]Homo sapiens (human)
NADH-ubiquinone oxidoreductase chain 4LAn NADH-ubiquinone oxidoreductase chain 4L that is encoded in the genome of human. [PRO:DNx, UniProtKB:P03901]Homo sapiens (human)
NADH-ubiquinone oxidoreductase chain 3An NADH-ubiquinone oxidoreductase chain 3 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P03897]Homo sapiens (human)
NADH-ubiquinone oxidoreductase chain 2An NADH-ubiquinone oxidoreductase chain 2 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P03891]Homo sapiens (human)
NADH-ubiquinone oxidoreductase chain 1An NADH-ubiquinone oxidoreductase chain 1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P03886]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 10An NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 10 that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 10, mitochondrialAn NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 10, mitochondrial that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] 1 subunit C2An NADH dehydrogenase [ubiquinone] 1 subunit C2 that is encoded in the genome of human. [PRO:DAN]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 7An NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 7 that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 2, mitochondrialAn NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 2, mitochondrial that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 8, mitochondrialAn NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 8, mitochondrial that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 4 An NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 4 that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 3An NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 3 that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 6An NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 6 that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] iron-sulfur protein 3, mitochondrialAn NADH dehydrogenase [ubiquinone] iron-sulfur protein 3, mitochondrial that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 1An NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 1 that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] iron-sulfur protein 6, mitochondrialAn NADH dehydrogenase [ubiquinone] iron-sulfur protein 6, mitochondrial that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] iron-sulfur protein 2, mitochondrialAn NADH dehydrogenase [ubiquinone] iron-sulfur protein 2, mitochondrial that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] iron-sulfur protein 7, mitochondrialAn NADH dehydrogenase [ubiquinone] iron-sulfur protein 7, mitochondrial that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] iron-sulfur protein 5An NADH dehydrogenase [ubiquinone] iron-sulfur protein 5 that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 2 An NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 2 that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] 1 subunit C1, mitochondrialAn NADH dehydrogenase [ubiquinone] 1 subunit C1, mitochondrial that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 3An NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 3 that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 5, mitochondrialAn NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 5, mitochondrial that is encoded in the genome of human. [PRO:DNx]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] iron-sulfur protein 4, mitochondrialAn NADH dehydrogenase [ubiquinone] iron-sulfur protein 4, mitochondrial that is encoded in the genome of human. [PRO:DNx, UniProtKB:O43181]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 1An NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:O15239]Homo sapiens (human)
Acyl carrier protein, mitochondrialAn acyl carrier protein, mitochondrial that is encoded in the genome of human. [PRO:DNx, UniProtKB:O14561]Homo sapiens (human)
Cytochrome c oxidase subunit NDUFA4A cytochrome c oxidase subunit NDUFA4 that is encoded in the genome of human. [PRO:DNx, UniProtKB:O00483]Homo sapiens (human)
NADH dehydrogenase [ubiquinone] iron-sulfur protein 8, mitochondrialAn NADH dehydrogenase [ubiquinone] iron-sulfur protein 8, mitochondrial that is encoded in the genome of human. [PRO:DNx, UniProtKB:O00217]Homo sapiens (human)

Compounds (8)

CompoundDefinitionClassesRoles
rotenoneDerris: A plant genus of the family FABACEAE. The root is a source of rotenoids (ROTENONE) and flavonoids. Some species of Pongamia have been reclassified to this genus and some to MILLETTIA. Some species of Deguelia have been reclassified to this genus.

rotenoid : Members of the class of tetrahydrochromenochromene that consists of a cis-fused tetrahydrochromeno[3,4-b]chromene skeleton and its substituted derivatives. The term was originally restricted to natural products, but is now also used to describe semi-synthetic and fully synthetic compounds.
organic heteropentacyclic compound;
rotenones
antineoplastic agent;
metabolite;
mitochondrial NADH:ubiquinone reductase inhibitor;
phytogenic insecticide;
piscicide;
toxin
daunorubicinanthracycline : Anthracyclines are polyketides that have a tetrahydronaphthacenedione ring structure attached by a glycosidic linkage to the amino sugar daunosamine.

daunorubicin : A natural product found in Actinomadura roseola.

Daunorubicin: A very toxic anthracycline aminoglycoside antineoplastic isolated from Streptomyces peucetius and others, used in treatment of LEUKEMIA and other NEOPLASMS.
aminoglycoside antibiotic;
anthracycline;
p-quinones;
tetracenequinones
antineoplastic agent;
bacterial metabolite
desacetyluvaricindesacetyluvaricin: isolated from Uvaria accuminata; structure given in first source
squamocinsquamocin: from seeds of Annona squamosa; a trihydroxy-bis-tetrahydrofuran fatty acid lactone; inhibits E. coli NADH:quinone oxidoreductase (NDH-1); structure given in first sourcepolyketide
auraptenaurapten: RN refers to (E)-isomer; structure given in first source

auraptene : A member of the class of coumarins that is umbelliferone in which the phenolic hydrogen has been replaced by a geranyl group. Ii is isolated from several edible fruits and vegetables and exhibits a variety of therapeutic properties.
coumarins;
monoterpenoid
antihypertensive agent;
antineoplastic agent;
antioxidant;
apoptosis inducer;
dopaminergic agent;
EC 2.7.11.24 (mitogen-activated protein kinase) inhibitor;
gamma-secretase modulator;
gastrointestinal drug;
hepatoprotective agent;
matrix metalloproteinase inhibitor;
neuroprotective agent;
plant metabolite;
PPARalpha agonist;
vulnerary
piericidin apiericidin A : A member of the class of monohydroxypyridines that acts as an irreversible mitochondrial Complex I inhibitor that strongly associates with ubiquinone binding sites in both mitochondrial and bacterial forms of NADH:ubiquinone oxidoreductase

piericidin A: pyridine-substituted fatty alcohol antibiotic; minor descriptor (75-85); on-line & Index Medicus search ANTIBIOTICS (75-85); RN given refers to (S-(R*,R*-(all-E)))-isomer
aromatic ether;
methylpyridines;
monohydroxypyridine;
secondary allylic alcohol
antimicrobial agent;
bacterial metabolite;
EC 1.6.5.3 [NADH:ubiquinone reductase (H(+)-translocating)] inhibitor;
mitochondrial respiratory-chain inhibitor
marminmarmin: structure in first source; RN given for (R-(E))-isomer
laherradurinlaherradurin: structure in first source