Spin trapping of superoxide radicals and peroxynitrite by 1-hydroxy-3-carboxy-pyrrolidine and 1-hydroxy-2,2,6, 6-tetramethyl-4-oxo-piperidine and the stability of corresponding nitroxyl radicals towards biological reductants.

Dikalov S, Skatchkov M, Bassenge E
Biochem Biophys Res Commun. 1997 231 (3): 701-4

PMID: 9070876 · DOI:10.1006/bbrc.1997.6174

The reactions of new spin trap 1-hydroxy-3-carboxy-pyrrolidine (CP-H) with superoxide radicals and peroxynitrite were studied. The rate constants were determined as 3.2 x 10(3) and 4.5 x 10(9) M-1s-1, respectively. It was found that 2mM of spin trap CP-H or 1-hydroxy-2,2,6,6-tetramethyl-4-oxo-piperidine (TEMPONE-H) provide almost the same spin trapping efficacy. In contrast to TEMPONE-H the reaction of CP-H with peroxynitrite was inhibited by 20 mM DMSO. This simplifies the quantification of peroxynitrite formation. During the reaction of CP-H and TEMPONE-H with superoxide radicals or peroxynitrite the stable nitroxide radicals 3-carboxy-proxyl (CP) and 2,2,6,6-tetramethyl-4-oxo-piperidinoxyl (TEMPONE) are formed. It was found that the rate of reduction of CP by glutathione or by smooth muscle cells was two-fold slower and the reduction of CP by ascorbate was 66-fold slower than corresponding rates of reduction of TEMPONE. Therefore quantification of the formation of superoxide radicals and of peroxynitrite by CP-H is much less hindered by a variety of biological reductants than in case of TEMPONE-H. Thus, CP-H is more suitable for spin trapping of superoxide radicals and peroxynitrite in biological systems than the TEMPONE-H.

MeSH Terms (12)

Animals Ascorbic Acid Cysteine Electron Spin Resonance Spectroscopy Glutathione Muscle, Smooth Nitrates Oxidation-Reduction Piperidines Pyrrolidines Spin Trapping Superoxides

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