A study of the mechanism of quercetin oxygenation by 18O labelling. A comparison of the mechanism with that of haem degradation.
The mechanism of quercetin oxygenation, which is formally analogous to haem degradation, was studied by using 18O labelling. In both the enzymic oxygenation (catalysed by quercetinase) and the non-enzymic reaction (base-catalysed), both oxygen atoms incorporated into product were derived from a single oxygen molecule. Quercetin oxygenation therefore occurs by a classical dioxygenase mechanism and is not an appropriate model for study of the mechanism of haem catabolism.
D049308:Dioxygenases; D005419:Flavonoids / Q000378:metabolism*; D006418:Heme / Q000378:metabolism; D008954:Models, Biological; D010084:Oxidation-Reduction; D010103:Oxygen Isotopes; D010105:Oxygenases / Q000302:isolation & purification / Q000378:metabolism; D011794:Quercetin / Q000378:metabolism*
D005419:Flavonoids; D010103:Oxygen Isotopes; D006418:Heme; D011794:Quercetin; D010105:Oxygenases; D049308:Dioxygenases; C003281:quercetin 2,3-dioxygenase