The reactions of hydroxylamine 1-hydroxy-2,2,6,6-tetramethyl-4-oxo-piperidine hydrochloride (TEMPONE-H) with peroxynitrite, superoxide and peroxyl radicals were studied. It was shown that under these reactions TEMPONE-H is oxidized into a stable nitroxide 1-hydroxy-2,2,6,6-tetramethyl-4-oxo-piperidi-noxyl (TEMPONE). The reactivity of TEMPONE-H towards reactive oxygen species was compared with the spin traps DMPO and TMIO as well as with DMSO and SOD. The rate constants of reactions of TEMPONE-H with peroxynitrite and superoxide radicals were 6 x 10(9) M(-1)s(-1) and 1.2x10(4) M(-1)s(-1), respectively. Using TEMPONE-H the sensitivity in the detection of peroxynitrite or superoxide radical was about 10-fold higher than using the spin traps DMPO or TMIO. Thus, TEMPONE-H may be used as a spin trap in chemical and biological systems to quantify peroxynitrite and superoxide radical formation.
Amidines Dimethyl Sulfoxide