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Literature summary for 1.13.11.24 extracted from

  • Wojdyla, Z.; Borowski, T.
    DFT study of the mechanism of manganese quercetin 2,3-dioxygenase quest for origins of enzyme unique nitroxygenase activity and regioselectivity (2016), J. Biol. Inorg. Chem., 21, 475-489 .
    View publication on PubMed
Search for more literature for 1.13.11.24

Metals/Ions

Metals/Ions Comment Organism Structure
Co2+ activates, Co-QDO Bacillus subtilis
Cu2+ activates, Cu-QDO, during the reaction mechanism of Cu-QDO dioxygen binds to the metal ion of the Cu-QDO-quercetin complex, yielding a Cu2+-superoxo quercetin radical intermediate, which then forms a Cu2+-alkylperoxo complex, the alkylperoxo complex evolves into endoperoxide intermediate that decomposes to the product Bacillus subtilis
Fe2+ activates, Fe-QDO Bacillus subtilis
Mn2+ activates, Mn-QDO, Mn2+ i the preferred metal ion. Mn-QDO in absence of O2 shows ability to react with nitroxyl (HNO)-singly reduced form of NO. HNO is incorporated into quercetin in the same manner as dioxygen, yet the reaction is strictly regioselective, as the only product is 2-((3,4-dihydroxyphenyl)(imino) methoxy)-4,6-dihydroxybenzoate Bacillus subtilis
additional information QDO is a mononuclear metalloenzyme hosting various transition metal ions (Cu2+, Mn2+, Fe2+) in its active site depending on the origin of the protein, different metal complex structures, overview Bacillus subtilis

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
quercetin + O2 Bacillus subtilis
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 2-(3,4-dihydroxybenzoyloxy)-4,6-dihydroxybenzoate + CO + H+
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 ?

Organism

Organism UniProt Comment Textmining
Bacillus subtilis
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-
-

Reaction

Reaction Comment Organism Reaction ID
quercetin + O2 = 2-(3,4-dihydroxybenzoyloxy)-4,6-dihydroxybenzoate + CO + H+ the enzyme incorporates both atoms of dioxygen into the substrate by cleaving the central heterocycle ring and releasing CO. The enzyme activates quercetin through deprotonation and the proton acceptor-Glu69 needs to reorient for the reaction to proceed. Energy profiles and reaction schemes for nonenzymatic nitroxygenation of quercetin monoanion. Transient and intermediate structures, catalytic mechaanism, detailed overview Bacillus subtilis
a

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
additional information Mn-QDO in absence of O2 shows ability to react with nitroxyl (HNO)-singly reduced form of NO. HNO is incorporated into quercetin in the same manneras dioxygen, yet the reaction is strictly regioselective, as the only product is 2-((3,4-dihydroxyphenyl)(imino)methoxy)-4,6-dihydroxybenzoate Bacillus subtilis ?
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 ?
quercetin + O2
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 Bacillus subtilis 2-(3,4-dihydroxybenzoyloxy)-4,6-dihydroxybenzoate + CO + H+
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 ?

Synonyms

Synonyms Comment Organism
Co-QDO
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 Bacillus subtilis
Fe-QDO
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 Bacillus subtilis
manganese quercetin 2,3-dioxygenase
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 Bacillus subtilis
Mn-QDO
-
 Bacillus subtilis
QDO
-
 Bacillus subtilis

General Information

General Information Comment Organism
additional information active site model, overview Bacillus subtilis
physiological function quercetin 2,3-dioxygenase (QDO) is an enzyme which accepts various transition metal ions as cofactors, and cleaves the heterocyclic ring of quercetin with consumption of dioxygen and release of carbon monoxide. QDO from Bacillus subtilis that binds Mn(II) displays an unprecedented nitroxygenase activity, whereby nitroxyl (HNO) is incorporated into quercetin cleavage products instead of dioxygen. The reaction proceeds with high regiospecificity, i.e. nitrogen and oxygen atoms of HNO are incorporated into specific fragments of the cleavage product. The reaction is an inherent property of the reactants, whereas the unique reactivity of Mn-QDO, as opposed to Co- or Fe-QDO that do not catalyze nitroxygenation. A nonenzymatic base-catalyzed reaction, which occurs in pH above 7.5, yields the same reaction products Bacillus subtilis