Detection of a C4a-Hydroperoxyflavin Intermediate in the Reaction of a Flavoprotein Oxidase
2008; American Chemical Society; Volume: 47; Issue: 33 Linguagem: Inglês
10.1021/bi801039d
ISSN1943-295X
AutoresJeerus Sucharitakul, Methinee Prongjit, Dietmar Haltrich, Pimchai Chaiyen,
Tópico(s)Biotin and Related Studies
ResumoThis 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.
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