Reactions of nitric oxide and nitrogen dioxide with coenzyme Q: involvement of the isoprenic chain

Paola Astolfi , Laurence Charles (1) , Didier Gigmes (1) , Lucedio Greci , Corrado Rizzoli (2) , Federico Sorana , Pierluigi Stipa

1 ICR - Institut de Chimie Radicalaire
2 GIAF - Dipartimento di Chimica Generale ed Inorganica, Chimica Analitica, Chimica Fisica,

The formation of a di-tert-alkyl nitroxide has been observed by Electron Spin Resonance during the exposure of coenzyme CoQ10, in both the oxidized and reduced forms, to nitrogen dioxide (˙NO2) or to nitric oxide (˙NO) in the presence of oxygen. The same kind of nitroxide has been observed also with CoQ1, CoQ3 or with 1-phenyl-3-methyl-2-butene, chosen as model compounds. In all cases, the formation of the nitroxide may be justified only by admitting the involvement of the isoprenic chain of the coenzymes and in particular the addition of ˙NO2 to the double bond. A mechanism which accounts for the formation of the nitroxide as well as the other compounds observed in the reactions is proposed and confirmed by a spectroscopic investigation (FT-IR, 1H NMR, X-ray analysis) and by ESI-MS.

Domains: Chemical Sciences

Paola Astolfi, Laurence Charles, Didier Gigmes, Lucedio Greci, Corrado Rizzoli, et al.. Reactions of nitric oxide and nitrogen dioxide with coenzyme Q: involvement of the isoprenic chain. Organic & Biomolecular Chemistry, 2013, 11 (8), pp.1399--1406. ⟨10.1039/C2OB27198B⟩. ⟨hal-01460439⟩