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Selective On/Off‐Nitroxides as Radical Probes to Investigate Non‐radical Enzymatic Activity by Electron Paramagnetic Resonance
Author(s) -
Duttagupta Indranil,
Jugniot Natacha,
Audran Gérard,
Franconi JeanMichel,
Marque Sylvain R. A.,
Massot Philippe,
Mellet Philippe,
Parzy Elodie,
Thiaudière Eric,
Vanthuyne Nicolas
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201800866
Subject(s) - nitroxide mediated radical polymerization , chemistry , electron paramagnetic resonance , moiety , photochemistry , stereochemistry , organic chemistry , nuclear magnetic resonance , radical polymerization , physics , copolymer , polymer
A nitroxide carrying a peptide specific to the binding pocket of the serine proteases chymotrypsin and cathepsin G is prepared. This peptide is attached as an enol ester to the nitroxide. Upon enzymatic hydrolysis of the peptide, the enol ester moiety is transformed into a ketone moiety. This transformation affords a difference of 5 G in phosphorus hyperfine coupling constant between the electronic paramagnetic resonance (EPR) signals of each nitroxide. This property is used to monitor the enzymatic activity of chymotrypsin and cathepsin G by EPR. Michaelis constants were determined and match those reported for conventional optical probes.