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Oxygen uptake after electron transfer from amines, amino acids and ascorbic acid to triplet flavins in air-saturated aqueous solution

Paper ID Volume ID Publish Year Pages File Format Full-Text
30756 44501 2007 8 PDF Available
Title
Oxygen uptake after electron transfer from amines, amino acids and ascorbic acid to triplet flavins in air-saturated aqueous solution
Abstract

The photolysis of lumichrome, riboflavin, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) was studied in air-saturated aqueous solution at room temperature in the presence of appropriate electron donors: ascorbic acid, aromatic amino acids or amines, e.g. ethylenediaminetetraacetate (EDTA). The overall reaction is conversion of oxygen via the hydroperoxyl/superoxide radical into hydrogen peroxide. The quantum yield of oxygen uptake increases with the donor concentration, e.g. up to 0.3 for riboflavin, FMN or FAD in the presence of EDTA or ascorbic acid (0.3–10 mM). The formation of H2O2 is initiated by quenching of the acceptor triplet state by the electron donor and subsequent reaction of the semiquinone radical with oxygen. Specific properties of flavins are discussed including the radicals involved and the pH and concentration dependences. The quantum yield of photodegradation is low under air, but substantial under argon, where the major product absorbing in the visible spectral range is the corresponding hydroquinone.

Keywords
Flavin; Radical; Triplet state; Photooxidation; Electron transfer
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Oxygen uptake after electron transfer from amines, amino acids and ascorbic acid to triplet flavins in air-saturated aqueous solution
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 87, Issue 2, 25 May 2007, Pages 73–80
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us