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ELECTROSTATIC EFFECTS IN THE PHOTOREDUCTION OF FLAVINS BY EDTA
Author(s) -
MOORE WILLIAM M.,
FIFE DENNIS J.,
GRABNER MARY JO,
WHYTE GRACE I.
Publication year - 1991
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.1751-1097.1991.tb03654.x
Subject(s) - flavin group , chemistry , flavin mononucleotide , intramolecular force , photochemistry , acceptor , electron donor , electron acceptor , excited state , reactivity (psychology) , electron transfer , hydrogen bond , aqueous solution , stereochemistry , catalysis , molecule , organic chemistry , enzyme , medicine , physics , alternative medicine , pathology , nuclear physics , condensed matter physics
— The anaerobic photoreduction of riboflavin, flavin mononucleotide, N(3)‐carboxymethylriboflavin, N(3)‐methyl‐lumiflavin, and lumiflavin by EDTA was studied in aqueous solution over the pH range 2.5–10. The electrostatic effects of the electron donor‐acceptor pair produce a secondary effect on the reactivity, and this effect can be predicted from the product of the charges (Z D x Z A ). The trianonic and tetraanonic species of EDTA have nitrogens which are free from intramolecular hydrogen bonding, and these species are potentially the most reactive. However, in some pH regions the electrostatic effect can become the dominant factor when both the electron donor and acceptor become negatively charged. The excited states of flavins are susceptible to charge effects whether the charge is localized on the side chain or involves the isoalloxazine ring system.