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KINETICS and THERMODYNAMICS OF THE AUTOXIDATION OF REDUCED FLAVIN MONONUCLEOTIDE (FMN)
Author(s) -
Lind Johan,
Merenyi Gabor
Publication year - 1990
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1990.tb01679.x
Subject(s) - autoxidation , flavin mononucleotide , flavin group , chemistry , semiquinone , reaction rate constant , radiolysis , kinetics , radical , photochemistry , electron transfer , inorganic chemistry , organic chemistry , redox , physics , quantum mechanics , enzyme
— Pulse radiolysis of flavin mononucleotide (FMN) solutions produce flavin semiquinone radicals. The equilibrium constant of radical formation was determined in the pH range2–7 as a function of flavin concentration. Several complex constants as well as the kinetics of equilibration were measured in this pH regime. The rate constant of the autoxidation of the free flavin mononucleotide semiquinone radical was determined to be (1 ± 0.5) × 10 4 M −1 s −1 . It is shown that between pH 2 and 7 the direct reaction of the dihydroflavin with oxygen is negligibly slow compared to the rate of autocatalysis. The autoxidation of dihydroflavin is discussed in relation to electron transfer theory.