Updated BioCyc iOS App now
available in iTunes store
Updated BioCyc iOS App now
available in iTunes store
Updated BioCyc iOS App now
available in iTunes store
Updated BioCyc iOS App now
available in iTunes store
Updated BioCyc iOS App now
available in iTunes store

MetaCyc Compound Class: an electron-transfer quinone

Superclasses: an acceptora redox electron carrierMembrane-Electron-Carriers
an aldehyde or ketonea ketonea cyclic ketonea quinone

This class holds quinones that are involved in electron transfer within membranes.

Quinones are organic compounds derived from aromatic compound, with two carbonyl groups incorporated into the ring structure with rearrangement of the double bonds where necessary. A classic example of a quinone is 1,4-benzoquinone. Quinones are commonly named with a prefix that indicates the parent aromatic hydrocarbon (for example, "benzo-" for benzene, "naphtho-" for naphthalene, and "anthra-" for anthracene) with a "-quinone" suffix.

Several types of quinones serve as electron acceptors in electron transport chains. Quinones can carry two electrons, and when fully reduced they are referred to as quinols. The addition of a single H atom to a quinone results in formation of a free radical called a semiquinone.

Many quinone derivatives often have other biological activities, such as vitamin K.

an electron-transfer quinone compound structure

Child Classes: a demethylmenaquinone (8), a menaquinone (19), a plastoquinone (2), a rhodoquinone (2), a ubiquinone (9), an anthraquinone (3)


SMILES: C1([R1])(=C([R4])C(=O)C([R3])=C([R2])C(=O)1)

Reactions known to consume the compound:

(5R)-carbapenem carboxylate biosynthesis , L-citrulline biosynthesis , L-Nδ-acetylornithine biosynthesis , L-proline degradation :
L-proline + an electron-transfer quinone[inner membrane] → (S)-1-pyrroline-5-carboxylate + an electron-transfer quinol[inner membrane] + H+

4-hydroxymandelate degradation :
(S)-4-hydroxymandelate + an electron-transfer quinone → 2-(4-hydroxyphenyl)-2-oxoacetate + an electron-transfer quinol

L-alanine degradation I :
D-alanine + an electron-transfer quinone[inner membrane] + H2O → ammonium + pyruvate + an electron-transfer quinol[inner membrane]

sulfide oxidation I (sulfide-quinone reductase) :
hydrogen sulfide + an electron-transfer quinone → intracellular S0 + an electron-transfer quinol

TCA cycle I (prokaryotic) :
(S)-malate + an electron-transfer quinone[inner membrane] → oxaloacetate + an electron-transfer quinol[inner membrane]

TCA cycle IV (2-oxoglutarate decarboxylase) , TCA cycle V (2-oxoglutarate:ferredoxin oxidoreductase) :
succinate[in] + an electron-transfer quinone[membrane] → fumarate[in] + an electron-transfer quinol[membrane]

TCA cycle VII (acetate-producers) :
(S)-malate + an electron-transfer quinone[inner membrane] → oxaloacetate + an electron-transfer quinol[inner membrane]
succinate[in] + an electron-transfer quinone[membrane] → fumarate[in] + an electron-transfer quinol[membrane]

trans-4-hydroxy-L-proline degradation I :
trans-4-hydroxy-L-proline[in] + an electron-transfer quinone[membrane] → (3R,5S)-1-pyrroline-3-hydroxy-5-carboxylate[in] + an electron-transfer quinol[membrane] + H+[in]

trans-lycopene biosynthesis II (plants) :
7,9,9'-cis-neurosporene + an electron-transfer quinone → prolycopene + an electron-transfer quinol
9,9'-di-cis-ζ-carotene + an electron-transfer quinone → 7,9,9'-cis-neurosporene + an electron-transfer quinol

UMP biosynthesis :
(S)-dihydroorotate + an electron-transfer quinone[inner membrane] → orotate + an electron-transfer quinol[inner membrane]

Not in pathways:
D-glucopyranose[out] + an electron-transfer quinone[membrane] + 2 H+[in] → D-glucono-1,5-lactone[out] + an electron-transfer quinol[membrane] + 2 H+[out]
NADPH + an electron-transfer quinone[inner membrane] + H+ → NADP+ + an electron-transfer quinol[inner membrane]
an electron-transfer quinone[inner membrane] + NAD(P)H + H+ → an electron-transfer quinol[inner membrane] + NAD(P)+
sn-glycerol 3-phosphate[in] + an electron-transfer quinone[membrane] → glycerone phosphate[in] + an electron-transfer quinol[membrane]
a D-amino acid[in] + an electron-transfer quinone[membrane] + H2O[in] → a 2-oxo carboxylate[in] + ammonium[in] + an electron-transfer quinol[membrane]

phenylacetate degradation II (anaerobic) :
phenylacetyl-CoA + 2 a quinone + H2O → 2 a quinol + phenylglyoxylyl-CoA

quinate degradation I :
L-quinate + a quinone → 3-dehydroquinate + a quinol

shikimate degradation I :
shikimate + a quinone → 3-dehydroshikimate + a quinol

thiosulfate oxidation II (via tetrathionate) :
2 thiosulfate + a quinone → tetrathionate + a quinol

Not in pathways:
a cyclic alcohol + a quinonea cyclic ketone + a quinol

Not in pathways:
a cyclic alcohol + a quinonea cyclic ketone + a quinol

Reactions known to produce the compound:

methane oxidation to methanol II :
methane + an electron-transfer quinol + oxygen → methanol + an electron-transfer quinone + H2O

partial TCA cycle (obligate autotrophs) :
succinate[in] + an electron-transfer quinone[membrane] ← fumarate[in] + an electron-transfer quinol[membrane]

Not in pathways:
2 an oxidized c-type cytochrome[out] + an electron-transfer quinol[membrane] → 2 a reduced c-type cytochrome[out] + an electron-transfer quinone[membrane] + 2 H+[in]

cuticular wax biosynthesis :
a secondary alcohol + an oxidized unknown electron acceptor → a ketone + an reduced unknown electron acceptor

Not in pathways:
a secondary alcohol + oxygen → a ketone + hydrogen peroxide

Not in pathways:
a nitroalkane + oxygen + H2O → an aldehyde or ketone + nitrite + hydrogen peroxide + H+

Reactions known to both consume and produce the compound:

nitrate reduction I (denitrification) , nitrate reduction VII (denitrification) :
nitrate + an electron-transfer quinol[inner membrane] ↔ nitrite + an electron-transfer quinone[inner membrane] + H2O

Not in pathways:
2 a quinone + NADPH + H+ ↔ 2 a semiquinone + NADP+

In Reactions of unknown directionality:

Not in pathways:
an oxidized coenzyme F420 + an electron-transfer quinol = a reduced coenzyme F420 + an electron-transfer quinone
NADH + an electron-transfer quinone + H+ = NAD+ + an electron-transfer quinol
an aldehyde + an electron-transfer quinone + H2O = a carboxylate + an electron-transfer quinol + H+
an (R)-2-hydroxyacid + an electron-transfer quinone = a 2-oxo acid + an electron-transfer quinol
formate + an electron-transfer quinone + H+ = CO2 + an electron-transfer quinol
9,9'-di-cis-ζ-carotene + 2 an electron-transfer quinone = prolycopene + 2 an electron-transfer quinol

Not in pathways:
2 a quinone + NADH + H+ = 2 a semiquinone + NAD+
1-(β-D-ribofuranosyl)-1,4-dihydronicotinamide + a quinone + H+ = a quinol + 1-(β-D ribofuranosyl)nicotinamide

Not in pathways:
a ketone + NADP+ = an enone + NADPH + H+
a secondary alcohol + an oxidized coenzyme F420 = a ketone + a reduced coenzyme F420
a secondary alcohol + NADP+ = a ketone + NADPH + H+
a secondary alcohol + NAD+ = a ketone + NADH + H+

In Redox half-reactions:
an electron-transfer quinone[membrane] + 2 H+[in] + 2 e-[membrane] → an electron-transfer quinol[membrane]

This compound has been characterized as a cofactor or prosthetic group of the following enzymes: putrescine oxidase

Created 31-Jan-2011 by Caspi R, SRI International


Allen73: Allen PC (1973). "Helminths: comparison of their rhodoquinone." Exp Parasitol 34(2);211-9. PMID: 4795616

Collins81: Collins MD, Jones D (1981). "Distribution of isoprenoid quinone structural types in bacteria and their taxonomic implication." Microbiol Rev 45(2);316-54. PMID: 7022156

Fujimoto12: Fujimoto N., Kosaka T., Yamada M. (2012). "Menaquinone as Well as Ubiquinone as a Crucial Component in the Escherichia coli Respiratory Chain." Chapter 10 in Chemical Biology, edited by D Ekinci, ISBN 978-953-51-0049-2.

Glover62: Glover, J., Threlfall, D. R. (1962). "A new quinone (rhodoquinone) related to ubiquinone in the photosynthetic bacterium Rhodospirillum rubrum." Biochem. J. 85:149.

Kassner75: Kassner EG, Klotz DH (1975). "Cholecystitis and calculi in a diverticulum of the gallbladder." J Pediatr Surg 10(6);967-8. PMID: 811785

Kawamukai02: Kawamukai M (2002). "Biosynthesis, bioproduction and novel roles of ubiquinone." J Biosci Bioeng 94(6);511-7. PMID: 16233343

Kita88: Kita K, Takamiya S, Furushima R, Ma YC, Suzuki H, Ozawa T, Oya H (1988). "Electron-transfer complexes of Ascaris suum muscle mitochondria. III. Composition and fumarate reductase activity of complex II." Biochim Biophys Acta 935(2);130-40. PMID: 2843227

Moore65: Moore HW, Folkers K (1965). "Coenzyme Q. LXII. Structure and synthesis of rhodoquinone, a natural aminoquinone of the coenzyme Q group." J Am Chem Soc 87;1409-10. PMID: 14293762

Ozawa69: Ozawa H, Sato M, Natori S, Ogawa H (1969). "Occurrence of rhodoquinone-9 in the muscle of Ascaris lumbricolides var. suis." Experientia 25(5);484-5. PMID: 5796154

Parson65: Parson WW, Rudney H (1965). "The biosynthesis of ubiquinone and rhodoquinone from p-hydroxybenzoate and p-hydroxybenzaldehyde in Rhodospirillum rubrum." J Biol Chem 240;1855-63. PMID: 14285535

Shimada01: Shimada H, Shida Y, Nemoto N, Oshima T, Yamagishi A (2001). "Quinone profiles of Thermoplasma acidophilum HO-62." J Bacteriol 183(4);1462-5. PMID: 11157962

Van95: Van Hellemond JJ, Klockiewicz M, Gaasenbeek CP, Roos MH, Tielens AG (1995). "Rhodoquinone and complex II of the electron transport chain in anaerobically functioning eukaryotes." J Biol Chem 270(52);31065-70. PMID: 8537365

Vermaas01: Vermaas WFJ (2001). "Photosynthesis and Respiration in Cyanobacteria." Encyclopedia of Life Sciences, Macmillan Publishers Ltd, Nature Publishing Group.

Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by Pathway Tools version 19.5 (software by SRI International) on Thu Apr 28, 2016, biocyc14.