Author/Editor     Šentjurc, M; Pečar, S; Chen, K; Wu, M; Swartz, H
Title     Cellular metabolism of proxyl nitroxides and hydroxylamines
Type     članek
Source     Biochim Biophys Acta
Vol. and No.     Letnik 1073, št. 2
Publication year     1991
Volume     str. 329-35
Language     eng
Abstract     Previous data from model systems indicated that the proxyl nitroxides should be especially resistant to bioreduction and therefore could be an effective solution to this often problematic characteristic of nitroxides. Therefore, we investigated the rate of reduction by cells and by the usual model system, ascorbate, of four proxyl nitroxides and three reference nitroxides. We found that, while the rate of reduction by ascorbate of the proxyl nitroxides was slower than the rate of a prototypic pyrrolidine nitroxide (PCA), the reverse was true for reduction by cells. We also studied the rate of oxidation of the corresponding hydroxylamines. The rate of oxidation by cells of the proxyl hydroxylamines was relatively fast, especially for the most lipophilic derivative. These results indicate that: (i) proxyl nitroxides may not be unusually resistant to bioreduction by functional biological systems; (ii) accurate knowledge of relative rates of metabolism of nitroxides and hydroxylamines in cells and tissues will require direct studies in these systems because the rates may not closely parallel those observed in model (chemical) systems; and (iii) proxyl nitroxides show potential value as agents to measure oxygen concentrations by the rates of oxidation of their corresponding hydroxylamines.
Descriptors     HYDROXYLAMINES
NITROGEN OXIDES
ASCORBIC ACID
BONE MARROW
CELL LINE
CELL MEMBRANE
ELECTRON SPIN RESONANCE SPECTROSCOPY
KINETICS
MICE
OXIDATION-REDUCTION
THYMUS GLAND