Selective On/Off‐Nitroxides as Radical Probes to Investigate Non‐radical Enzymatic Activity by Electron Paramagnetic Resonance. Issue 30 (3rd May 2018)

• Record Type: Journal Article
• Authors: Duttagupta, Indranil; Jugniot, Natacha; Audran, Gérard; Franconi, Jean‐Michel; Marque, Sylvain R. A.; Massot, Philippe; Mellet, Philippe; Parzy, Elodie; Thiaudière, Eric; Vanthuyne, Nicolas
• Is Part Of: Chemistry. Volume 24:Issue 30(2018)
• Page Start: 7615
• Page End: 7619
• Publication Date: 2018-05-03
• Subjects: enzymatic activity -- EPR spectroscopy -- Michaelis constants -- nitroxides -- selectivity; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201800866
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: 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. Abstract : Radical sign : The enzymatic activities of chemotrypsin and cathepsin G were detected by electronic paramagnetic resonance spectroscopy through a unique signal using specific peptide‐labelled nitroxides.