Jeerus SucharitakulMethinee ProngjitDietmar HaltrichPimchai ChaiyenChulalongkorn UniversityMahidol UniversityUniversity of Natural Resources and Applied Biotechnology2018-07-122018-07-122008-08-19Biochemistry. Vol.47, No.33 (2008), 8485-8490000629602-s2.0-49749144875https://repository.li.mahidol.ac.th/handle/123456789/18873This work describes for the first time the identification of a reaction intermediate, C4a-hydroperoxyflavin, during the oxidative half-reaction of a flavoprotein oxidase, pyranose 2-oxidase (P2O) from Trametes multicolor, by using rapid kinetics. The reduced P2O reacted with oxygen with a forward rate constant of 5.8 × 104 M-1 s-1 and a reverse rate constant of 2 s-1, resulting in the formation of a C4a-hydroperoxyflavin intermediate which decayed with a rate constant of 18 s-1. The absorption spectrum of the intermediate resembled the spectra of flavin-dependent monooxygenases. A hydrophobic cavity formed at the re side of the flavin ring in the closed state structure of P2O may help in stabilizing the intermediate. © 2008 American Chemical Society.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyMedicineArticleSCOPUS10.1021/bi801039d