Quercetin dioxygenase

Speier G (1993) Copper dioxygenation chemistry relevant to quercetin dioxygenase. In Karlin KD, Tyeklar Z (eds) Bioinorganic chemistry of copper. Chapman 8c Hall, London... 

The bacterial degradation of quinoline heterocycles proceeds via oxidation to 3-hydroxy-4-oxoquinolines, which are substrates for a novel family of dioxygenases. The reaction is similar to the copper-dependent quercetin dioxygenase (see Section 8.16.4.2), involving oxidative cleavage of two C—C bonds, and liberation of carbon monoxide however, remarkably, these enzymes have no cofactor requirement. Two dioxygenases QDO... 

The transformations described above constitute models for several oxidations (see Figure 10) catalyzed by copper-dependent mono- and dioxygenases [2,3]. Reactions (18) and (19), for example, are models for trypophan dioxygenase (EC 1.13.11.11) and quercetin dioxygenase (EC 1.13.11.24), respectively. Other examples include dopamine monooxygenase (EC 1.14.17.1) and tyrosinase (EC 1.14.18.1). 

Copper dioxygenase Quercetinase Fungal Quercetin oxidative cleavage... 

MONOPHENOL MONOOXYGENASE NITRITE REDUCTASE PHOTOSYSTEM I QUERCETIN 2,3-DIOXYGENASE SUPEROXIDE DISMUTASES COPROPORPHYRINOGEN OXIDASE... 

PROTOPORPHYRINOGEN OXIDASE PUTRESCINE OXIDASE PYRUVATE OXIDASE QUERCETIN 2,3-DIOXYGENASE... 

PROTOCATEGHUATE 3,4-DIOXYGENASE PROTOCATECHUATE 4,5-DIOXYGENASE 2-Protocatechuoylphloroglucinolcarboxylate, QUERCETIN 2,3-DIOXYGENASE PROTOCHLOROPHYLLIDE REDUCTASE PROTOGENIC PROTOPHILIC AMPHIPROTIC... 

Quercetinase (Quercetin 2,3-dioxygenase. EC 1.13.11.24) is the only dioxygenase known to contain copper as the sole cofactor194. The enzyme catalyzes the reaction shown in Eq. (21). 

Oxygenation and cleavage of the fiavonolate in these complexes are observed which mimic that of quercetin 2,3-dioxygenase. For example, the red complex [Cu(I)(bipy)2]2 [Cu(I)(flavonolate)3] turns into green with absorptions 421 and 615 nm (e = 14,100 and... 

FIGURE 23. Oxidation mechanism of quercetin catalyzed by quercetin 2,3-dioxygenase with O shown in boldface... 

Figure 26 Reaction scheme for quercetin 2,3-dioxygenase. The proposed substrate-Cu complex is shown with quercetin (5,7,3, 4 -tetrahydroxyflavonol). Reproduced from F. Fusetti K. H. Schroter R. A. Steiner P. I. van Noort T. Pijning ...

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