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Quantitative structure activity relationships for the electron transfer reactions of Anabaena PCC 7119 ferredoxin‐NADP + oxidoreductase with nitrobenzene and nitrobenzimidazolone derivatives: mechanistic implications
Author(s) -
Anusevicius Zilvinas,
Soffers Ans E.M.F,
Cenas Narimantas,
Sarlauskas Jonas,
Martinez-Julvez Marta,
Rietjens Ivonne M.C.M
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)00464-0
Subject(s) - ferredoxin , oxidoreductase , ferredoxin—nadp(+) reductase , nitrobenzene , chemistry , electron transfer , anabaena , stereochemistry , biochemistry , photochemistry , catalysis , enzyme , cyanobacteria , biology , bacteria , genetics
The steady state single electron reduction of polynitroaromatics by ferredoxin‐NADP + oxidoreductase (EC 1.18.1.2) from cyanobacterium Anabaena PCC 7119 has been studied and quantitative structure activity relationships are described. The solubility of the polynitroaromatics as well as their reactivity towards ferredoxin‐NADP + oxidoreductase are markedly higher than those for previously studied mononitroaromatics and this enabled the independent measurement of the kinetic parameters k cat and K m . Interestingly, the natural logarithm of the bimolecular rate constant, k cat / K m , and also the natural logarithm of k cat correlate with the calculated energy of the lowest unoccupied molecular orbital of the polynitroaromatic substrates. The minimal kinetic model in line with these quantitative structure activity relationships is a ping‐pong mechanism which includes substrate binding equilibria in the second half reaction.