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MetaCyc Compound: pyrroloquinoline quinone

Synonyms: coenzyme PQQ, 4,5-dihydro-4,5-dioxo-1H-pyrrolo[2,3-5,6]quinoline-2,7,9-tricarboxylic acid, 2,7,9-tricarboxy-1H-pyrrolo(2,3-f)quinoline-4,5-dione, 2,4,6-tricarboxylic-pyrrolo[2,3-5,6]quinoline 8,9-quinone, 4,5-dioxo-3α,4,5,6,7,8,9,9β-octahydro-1H pyrrolo[2,3-f]quinoline-2,7,9-tricarboxylate, 4,5-dioxo-4,5-dihydro-1H-pyrrolo[2,3-f]quinoline-2,7,9-tricarboxylate, PQQ, methoxatin, 2,7,9-tricarboxy-1H-pyrrolo[2,3-f]quinoline-4,5-dione

Superclasses: an aldehyde or ketonea ketonea cyclic ketonea quinone

Pyrroloquinoline quinone (PQQ) is water-soluble, redox-cycling orthoquinone that was initially isolated from cultures of methylotropic bacteria. It has been found to be a cofactor of several bacterial enzymes, and is present in many animal tissues [Bishop98, Anthony01]. Several researchers suggested that PQQ should be considered a member of the vitamin B group [Kasahara03] although this claim has been contested [Felton05].

Chemical Formula: C14H3N2O8

Molecular Weight: 327.19 Daltons

Monoisotopic Molecular Weight: 330.01241517980003 Daltons

pyrroloquinoline quinone compound structure

SMILES: C2(C(=NC3(C(=O)C(=O)C1(C=C(C(=O)[O-])NC=1C(C=2C(=O)[O-])=3)))C(=O)[O-])

InChI: InChI=1S/C14H6N2O8/c17-10-4-2-6(14(23)24)15-8(4)7-3(12(19)20)1-5(13(21)22)16-9(7)11(10)18/h1-2,15H,(H,19,20)(H,21,22)(H,23,24)/p-3


Unification Links: CAS:72909-34-3, ChEBI:58442, ChemSpider:19951489, DrugBank:DB03205, HMDB:HMDB13636, KEGG:C00113, PubChem:23615439

Standard Gibbs Free Energy of Formation (ΔfG in kcal/mol): -222.46518Inferred by computational analysis [Latendresse13]

Reactions known to consume the compound:

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:

pyrroloquinoline quinone biosynthesis :
6-(2-amino-2-carboxyethyl)-7,8-dioxo-1,2,3,4,7,8-hexahydroquinoline 2,4-dicarboxylate + 3 oxygen → pyrroloquinoline quinone + 2 hydrogen peroxide + 2 H2O + H+

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:

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

In Reactions of unknown directionality:

Not in pathways:
myo-inositol + pyrroloquinoline quinone = 1-keto-D-chiro-inositol + pyrroloquinoline 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+

Enzymes activated by pyrroloquinoline quinone, sorted by the type of activation, are:

Activator (Mechanism unknown) of: manganese-oxidizing peroxidase [Johnson08], manganese-oxidizing peroxidase [Anderson09]

This compound has been characterized as a cofactor or prosthetic group of the following enzymes: glucose dehydrogenase, aldose sugar dehydrogenase, dehydrodiconiferyl alcohol dehydrogenase, alcohol dehydrogenase, glucose dehydrogenase, alcohol dehydrogenase, polyvinyl alcohol dehydrogenase, cyclic alcohol dehydrogenase, L-sorbosone dehydrogenase, acrylonitrile hydratase, D-glucose dehydrogenase, 2-chloroethanol dehydrogenase, L-sorbosone dehydrogenase, quinate dehydrogenase, shikimate dehydrogenase, alcohol dehydrogenase, D-sorbitol dehydrogenase, dopamine β-monooxygenase, N-methylputrescine oxidase, methanol dehydrogenase, methanol dehydrogenase, methanol dehydrogenase


Anderson09: Anderson CR, Johnson HA, Caputo N, Davis RE, Torpey JW, Tebo BM (2009). "Mn(II) oxidation is catalyzed by heme peroxidases in "Aurantimonas manganoxydans" strain SI85-9A1 and Erythrobacter sp. strain SD-21." Appl Environ Microbiol 75(12);4130-8. PMID: 19411418

Anthony01: Anthony C (2001). "Pyrroloquinoline quinone (PQQ) and quinoprotein enzymes." Antioxid Redox Signal 3(5);757-74. PMID: 11761326

Bishop98: Bishop A, Gallop PM, Karnovsky ML (1998). "Pyrroloquinoline quinone: a novel vitamin?." Nutr Rev 56(10);287-93. PMID: 9810806

Felton05: Felton LM, Anthony C (2005). "Biochemistry: role of PQQ as a mammalian enzyme cofactor?." Nature 433(7025);E10; discussion E11-2. PMID: 15689995

Johnson08: Johnson HA, Tebo BM (2008). "In vitro studies indicate a quinone is involved in bacterial Mn(II) oxidation." Arch Microbiol 189(1);59-69. PMID: 17673976

Kasahara03: Kasahara T, Kato T (2003). "Nutritional biochemistry: A new redox-cofactor vitamin for mammals." Nature 422(6934);832. PMID: 12712191

Latendresse13: Latendresse M. (2013). "Computing Gibbs Free Energy of Compounds and Reactions in MetaCyc."

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
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