Evidence of overestimation of rate constants for the superoxide trapping by nitrones in aqueous media.
Since major disagreements exist regarding the kinetics of superoxide trapping by nitrones, the underlying theory of one of the most popular method used in these studies was reinvestigated. It involves a competition between the nitrone of interest and a superoxide scavenger, and implies that the superoxide spontaneous dismutation, the spin adduct decay, and the consumption of the competitor during the course of the experiments are negligible events. Evidences of the importance of these three unduly neglected reactions are given, and errors connected to their omission are estimated. Hence this Stern-Volmer-like method should be avoided in the determination of rate constants for the trapping of superoxide by nitrones.
Laboratoire TRACES, JE 2421, Case 541, Université de Provence, Faculté de Saint Jérôme, Av. Escadrille Normandie Niemen, 13397 Marseille Cedex 20, France.
Robert P
RP
Lauricella
Jean-Claude H
JC
Bouteiller
Béatrice N
BN
Tuccio
D003497:Cyclic N-Oxides / Q000737:chemistry; D019271:Hypoxanthine / Q000737:chemistry; D007700:Kinetics; D008958:Models, Molecular; D009589:Nitrogen Oxides / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry; D013481:Superoxides / Q000737:chemistry*; D014867:Water; D019820:Xanthine / Q000737:chemistry; D014969:Xanthine Oxidase / Q000737:chemistry / Q000378:metabolism
C510912:(diethoxyphosphoryl)-5-methylpyrroline N-oxide; D003497:Cyclic N-Oxides; D009589:Nitrogen Oxides; D011758:Pyrroles; C015388:nitrones; D014867:Water; D013481:Superoxides; D019820:Xanthine; D019271:Hypoxanthine; D014969:Xanthine Oxidase