Abstract
Free radical formation from VP 16-213 was studied by ESR spectroscopy. Incubation of VP 16-213 with the one-electron oxidators persulphate-ferrous, myeloperoxidase (MPO)/hydrogen peroxide and horseradish peroxidase (HRP)/hydrogen peroxide readily led to the formation of a free radical. The ESR spectra obtained in the last two cases, were in perfect accord with that of a product obtained by electrochemical oxidation of VP 16-213 at +550 mV. The half-life of the free radical in 1 mM Tris (pH 7.4), 0.1 MNaClat 20°C, was 257 ± 4 s. The signal recorded on incubation with HRP/H2O2 or MPO/H2O2 did not disappear on addition of 0.3 - 1.2 mg/ml microsomal protein. From incubations with rat liver microsomes in the presence of NADPH, no ESR signals were obtained.
Original language | English (US) |
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Pages (from-to) | 263-272 |
Number of pages | 10 |
Journal | Free Radical Research |
Volume | 1 |
Issue number | 4 |
DOIs | |
State | Published - 1986 |
Externally published | Yes |
Keywords
- Antineoplastic Agent
- Electron Spin Resonance
- Free Radicals
ASJC Scopus subject areas
- Biochemistry