QUANTIFICATION OF PEROXYNITRITE, SUPEROXIDE, AND PEROXYL RADICALS BY A NEW SPIN TRAP HYDROXYLAMINE 1-HYDROXY-2,2,6,6-TETRAMETHYL-4-OXO-PIPERIDINE

The reactions of hydroxylamine 1-hydroxy-2,2,6,6-tetramethyl-4-oxo-pip eridine hydrochloride (TEMPONE-H) with peroxynitrite, superoxide and p eroxyl radicals were studied. It was shown that under these reactions TEMPONE-H is oxidized into a stable nitroxide 1-hydroxy-2,2,6,6-tetram ethyl-4-oxo-piperidinoxyl (TEMPONE). The reactivity of TEMPONE-H towar ds reactive oxygen species was compared with the spin traps DMPO and T MIO as well as with DMSO and SOD. The rate constants of reactions of T EMPONE-H with peroxynitrite and superoxide radicals were 6x10(9) M(-1) s(-1) and 1.2x10(4) M(-1)s(-1), respectively. Using TEMPONE-H the sens itivity in the detection of peroxynitrite or superoxide radical was ab out 10-fold higher than using the spin traps DMPO or TMIO, Thus, TEMPO NE-H may be used as a spin trap in chemical and biological systems to quantify peroxynitrite and superoxide radical formation. (C) 1997 Acad emic Press